Building a stroker with overdrive.

[375instroke]

My plans are for a dry weather daily driver.  I have an A-518/Ultrabell combo.  Will run B-body HP exhaust.  Thinking of a roller cam.  I wanted a solid flat tappet cam, but all the oil/flat cam problems has me worried.  All new cars run roller, but I hear the retrofit rollers need constant spring and lifter replacement.  I don't mind the initial cost, and I like doing valve adjustments, but I would hate the spring and lifter, and perhaps rocker arm replacement every 10,000 miles.  I need a broad power curve since I will be cruising at low RPM with the overdrive and stock converter.  Don't know if 500" is too much.  By this, I mean would there be too much unusable torque and too low of an RPM peak?  I'll run the 440Source heads, so you know the flow I'll have, but headers are out of the question.  I'll probably run an Edelbrock RPM intake.  While playing with CompCams, solids, hydraulics, rollers, and flat tappets, in Dyno2003, the best cam I can find, meaning it has the highest torque and horsepower curves, is the XR280R.  I have an XS274S and XS282S, both solid flat tappet cams, for comparison.  The hydraulic rollers and flat hydraulics have much lower numbers in the simulations.  I only have 3.23 gears now.  With the .69:1 overdrive, 4.11s would be like 2.84 gears in 4th.  4.11s will put me at 2300RPM at 60MPH, and 2650RPM at 70MPH.  3.91s put me at 2150@60 & 2550@70.  3.23s would drop me down to 1800@60.  I'll just get whatever gear would be best.  I also have Drag2003 that I'm running numbers through, but it's all educated guess work, isn't it?  Most of this build comes up in the 11.75 to 12.50 in the 1/4 at 110MPH to 117MPH range.  Remember, daily driver.  Where should I go with this?  Should I just buy parts and get it over with?  I can drag this thing on forever analyzing things.

Here's the numbers I used for the heads:

	Intake	Exhaust
.100	82	81
.200	178	147
.300	231	169
.400	247	194
.500	292	211
.600	300	224
.700	301	231

Here are the cams:









Here's the dyno plot:

[firefighter3931]

If you're looking for low maintenance and reliability in a roller cam....a hydraulic roller will be your best choice. No wild spring pressures to contend with and a standard iron ductile rocker arm will work fine. Many of these hyd rollers use spring pressures in the flat tappet range (350-375lbs) so you don't need exotic valvetrain parts.

With a standard port head on a 500in engine it will peak before 6k anyway so there shouldn't be any valve float issues to worry about. If you're intent on running HP manifolds then the cam should be custom ordered with wider lobe centers to reduce overlap. This helps with scavenging and intake reversion.


Have a look at MFR426's build in the proven combo section....it's very similar to what you're wanting to build. 



Ron

[375instroke]

When running the iterator in Dyno2003, it liked a lot more exhaust duration, like up to 20 degrees more, which seems intuitive, but I've seen motors with restrictive exhaust systems that didn't respond the way you think they would when adding more exhaust duration, but there could have been more going on.  How does the exhaust lift affect things?  I've seen split cams, ones with more exhaust duration than intake, where the exhaust has more lift than the intake, and some where they have less lift than the intake, and both made by the same manufacturer.  I think the flow to lift ratio has something to do with the valve size, where once you reach a certain lift, as a percentage of the valve size, the valve becomes less and less of a hindrance to the flow, and opening it more does little more than wear out things faster.

[aifilaw]

Engine Simulators are equations that take input and produce output.
As with all simulations, expect a slight difference between what you put in, and what you get out. Instead understand why a certain change yields a certain result and you will build a better engine. Your questions lead me to believe you are working in that direction.
Those cylinder head flow numbers are indicative of stealth heads with a 1-way valve job, or edelbricks with some light work on the ports and a 3-way valve job. Like I said, a simulation or computer is only as good as the numbers you put in...if you are off by 5% on the input, you can expect to be off at least 5% on the output.

Adding more exhaust duration to a restrictive exhaust compounds the problem, what the program is attempting to simulate and is most probably averaging is exhaust pressure and velocity of the air, if you have a large static pressure built in the exhaust piping, then your increased duration is simply going to assist in that pressure vessel, split-pattern cams work exceptionally well in an imbalanced head (intake side far superior in flow differential to the exhaust). That is why on iron head old mopar BB's a 214-234 made far more total power under the curve, and often maximum power than a 234-234.
That's not to say that your intake and exhaust ports should be equal, with a naturally aspirated engine your sucking air in using the piston, and partially assisted by the other ports. In the case of the exhaust, you are pushing the expended gas out, but you are assisted by suction from the exhaust network of pipes, and additionally by the expanded gas being too large for the cylinder even at full stroke, that is why the exhaust valve is smaller.
A "perfect" equilibrium of these two is paramount, and you can see the example in an L92 head for example on an LS series chevy block when a split pattern camshaft makes far LESS power than a single cam, and actually a little less power than a split pattern in the other regard "224-218" for example.
If we get into assisted applications (forced induction, et cetera) then it changes the conversation, but not the basics.

firefighter answered the questions on the valvetrain, I agree, hydraulic roller will be superior for low maintainance. I've dealt with PITA solid valvetrains for too long, adjusting them is not worth it anymore. hydraulic rollers are the way to go, and 90% of all cars you see on the road run them just fine.

Valve lift is a function of the head's flow, if the head is making 292 at .5 and 300 at .6 and 301 at .7, having a cam that goes over 0.500 is fundamentally nearly pointless.... having a cam that keeps you at or near 0.5 for a longer period in the middle of the lobe becomes very important, but then you must sacrifice either your overlap, or opening or closing, or your ramp rate.
Overlap can be turned into a good thing to help with detonation and reduce your dynamic compression ratio, or it could be a bad-thing if you back-cut the intake and it back-flows. A more aggressive ramp rate can be achieved on a hydraulic roller because its.... a roller. But going too far and you are going to stress or limit the lifespan of your pushrods, springs, lifters and rockers.

Ask questions, you are on the right track...

Hmmm, it seems as though Chryco relinquished his title when I took my sabbatical of summing up my 14-page dissertations that ramble off onto answering questions that weren't asked in too much detail, into 3 sentences and Ron will be taking up where he left off since no one can understand me
Howdy Ron.

[firefighter3931]

Aiflaw made some good observations regarding the split pattern cam profiles. 

The split pattern grinds were used primarily to offset the intake/exhaust flow ratios. The generally accepted optimal ratio is 70% meaning that the exhaust port flows 70% of the intake side. Factory heads flow well short of that so with a stock or slightly modified head the split pattern stick helps be allowing the engine to exhale better by hanging the valve open longer.

The different lifts between intake and exhaust is just a function of that particular cam grinders preference. Most companies have a master lobe library and will mix and match different intake and exhaust profiles to suit a specific build. For example : Some cam grinders prefer an agressive intake lobe for increased cylinder filling and a slower closing exhaust lobe to help with breathing. These are generally "custom" grinds...

Regarding the manifolds : Basicly, the restrictive exhaust will limit the cam choice to a large extent. The split pattern grinds don't seem to show significant gains because the exhaust manifold is the restriction. A good friend of mine and master head porter does the headwork and cam selection for most of the FAST racers who have to use stock heads, stock intake and stock exhaust manifolds. In conversations with Dwayne on the head porting end of the FAST builds his commment regarding exhaust port headwork was that it was minimal. I asked why and his comments were basicly that it didn't make much difference because the exhaust manifold is the restriction. 


If you're looking for a good exhaust manifold grind my suggestion would be to get on the phone with Dwayne at PRH and have him spec out a nice custom stick for your build. He has done a bunch of dyno testing with different cam profiles and factory manifolds and knows what works and what doesn't. 


Porter Racing Heads : 802-951-1955



Ron

[Mike DC]

I know what you're thinking with the headers & stock manifolds.  But think about it - there are millions of regular-production vehicles these days with headers right from the factory.  It has really become a normal thing now in the auto industry. 

Just use stainless pipes so they never rust, have them made with flanges as thick as a dictionary, and use a ball-type connector where they meet the rest of the exhaust system.  That makes a huge difference. 

(And there's no law saying that you have to jump right from stock manifolds all the way to full-length tuned 2" head pipes with 3.5" collectors.  Even a half-sized set of headers is still lightyears better for the motor than the stock iron logs.)

[375instroke]

Maybe for another car, but this isn't an all out effort.  I just like the look of stock Mopar engines, and that is rather important to me.  I could put together a turbo ricer that runs 10s, but that's not the point.  Looks like some of you like long posts, so here I go.  I promise I'll get back on topic soon.

A guy at work inherited a '31 Ford roadster from his wife's father with a flathead he, or someone, put together in the '50s.  Fenders removed, flat black primer, typical look, but period correct.  Sure, it may look like all the others, but really?  How many are actually running around?  How many with Chevy small blocks?  Yuck.  Great looking car.  Decent, no frills interior, pie crust tires with wide white walls and red wheels.  No rust.  Sure, he could make it faster with modern parts, but why?  I can't stand billet parts, digital gauges, IFS, tilt columns, and all that crap, on that kind of car.  Really, not on any car.  Even worse is when people imitate a beat up car.  Airbrushing rust spots.  Swede paint.  Did swede paint come from someone seeing a really old car with faded paint, and think, "How'd that guy get his car to look like that?"  Back to the '31.  He noticed some water in the oil, so he tore the motor apart, and noticed it was still standard bore.  We were looking for information online on Ford flathead V8s, and he was telling me what a bastardized motor it was, with a this year block, and that year water pump and heads, and stuff like that, when I told him the car looked great, and then showed him this picture.  Now this just brought a tear to my eye.



Well, the car this motor is for, is a '69 Swinger, rust free, original paint Y2 yellow, column shift 273/904 combo, rubber floor mat, bench seat, column shift.  It had 13" wheels, but I put 14X5.5 steels and those fake mag wheel hub caps with the lugs on them.  It'll get dog dishes when I'm done.  I had a GTS hood I was going to use, but someone stole it, so I'm just going to go sleeper with it.  When I open the hood, I want it to look like it came that way.  No TTIs, which is what I would use if I was going to run headers, and I won't use Schumacher's.  They just seem like a compromise to me.  I was going to say they aren't any bigger than the manifolds, but decided to measure.  The 906 heads have a 1.66" exit window, and the Schumacher tri-ys have a 2.07" cross section.  2" headers have a 3.14" cross section--almost twice the size of the stock heads.  Wow!  Well, as the car sits now, the K-frame scrapes the ground sometimes in Seattle.  What would happen to the headers?  One can only tuck up a 3-1/2" collector so far.  The pics I've seen of the A-518 oil pan look like it hangs low, but I think it can go up higher.  The bench seat will cover up anything I do to the tunnel, so I can put it up as high as I want.

When using Dyno2003, all the cams of similar duration to the solid roller all come out pretty close.  All I have to work with is the advertised and .050" lifts, and the program uses these to guess the aggressiveness of the cam, so I don't know if they have any approximation with reality.  You know, garbage in, garbage out.  Here's the plot:



Here's what they look like with large tube headers:



Here's the XR280R solid roller with headers and with manifolds:



Here's the flat hydraulic with large tube headers next to the solid roller with manifolds.  Almost the same graph:



Even with the manifolds, Drag2003 puts the car at mid 11 quarters, which is plenty fast for me.  The fastest car I've owned was a '69 Coronet with a junk yard 440 and 3.91 Sure-Grip, that ran 14.20@98MPH.  Could I be unhappy with a build like this?  Most posts on stroker motors say at least 250deg@.050 and .550" lift, or the motor/car will be a turd.  Maybe that's only with flat hydraulics.  Any more input or suggestions is greatly appreciated.  Also, I added the other cam types and changed the dyno plot in the original post to make it look like these ones.

[firefighter3931]

Well, the car this motor is for, is a '69 Swinger, rust free, original paint Y2 yellow, column shift 273/904 combo, rubber floor mat, bench seat, column shift. 

The HP manifolds might present some challenges with an RB engine in an a-body. The 383 GTS Darts used a driver side specific exhaust manifold to clear the steering colomn and it was significantly more restrictive than the standard b-body HP part. I'm not even sure if you could feasably run any manifold in that chassis with a raised deck engine ?

Maybe you should visit the Big Block Dart website and poke around for some tech advice....those guys have lots of experience with BB engines and A-bodies. 

Your best choice for ease of installation and fitment is going to be a B-based engine (383-400) with the shorter deck. There are some good stroker kits available for both the 383 and 400 blocks. If your goal is mid 11's you don't need a 500in stroker....a 3.75-3.90 stroke 383/400 will hit that mark pretty easy with the right combination of parts.

I know you're really wanting to use a factory manifold but that is going to be a huge liability and power killer.  The only way it can work would be with a lowdeck engine and an original 383 GTS driver side exhaust manifold.

Fwiw, the GTS engine was down 30hp vs the standard 383 magnum when installed in the a-body. The exhaust manifolds were the reason why. How much power would it lose with a 500hp engine combination ?



Ron

[375instroke]

The BigBlockDart.com site shows the B-body manifolds with both B and RB motors if you want to see how they fit.  Yes, it is tight.  The outer tube of the steering column needs to be cut back to the firewall, and this is how my friend fit them in his '67 Barracuda with a 440 in the early '90s with a DC K-frame copy.  My problem will be with the column shifter linkage.  I have a 440, and was going to use it, but had a hard time finding bucket seats and console set-up, so column/bench it will stay.  I have a 400 block now, too, and think that I can trim the outer tube of the column, put a bushing farther up into the tube to hold the shifter tube, trim the shift tube to clear the manifold if needed, and strengthen what's left, if needed.  Power steering will be used also, and it fit in the Barracuda, so I don't see any problems.  Here's a sample pic of the B manifold in an A, followed by the stock A manifold for those interested.  Doesn't look like I could fit a fish tape through that thing.





The idea for this is low RPM, quiet exhaust, OD transmission, daily driver-ish (?) sleeper.  I want the motor in it's power band while cruising for economy (Don't laugh.  Just don't want 8MPG), reliability, and longevity.  Is my head up my ass with this?

I am over on the BigBlockDart.com site most days, and Moparts.com, but not so much any more.  I haven't owned a Charger since the '90s, but they are my first love, and that's why I am on this board, too.  I've read lots of great information and advice you've given over the years.  Thanks.

[firefighter3931]

Well, it appears you have done your homework and are top of things ! 


Looking at that pic of the engine on the stand you can see how pinched that driver side manifold is to allow for steering colomn clearance. The other pic illustrates how close the master cylinder the manifold is....i would be concerned with radiant heat and brake fluid boiling. Perhaps the M/C could be relocated ?

What do the guys on BB Dart say about HP/TQ numbers with these manifolds ? Has anyone actually dynoed an engine and experimented with different cam profiles to see what works and what doesn't ?


As you probably know those engine simulation programs are often unrealistic. Real world numbers are often quite humbleing. I can assure you that none of the max effort FAST (Stroker) builds with lots of compression (13:1) using fully scienced out heads and the higher flowing B-body HP manifolds make the kind of power shown in your manifold simulation program. 

I realize this is not a max-effort build so i guess the only answer really is to build it and live with the results....whatever they may be. 


Honestly, mid 11's in an a-body should be a cakewalk, even with a crummy exhaust. The cam will need to be ground on a wide LSA to reduce overlap and help with scavenging. This is one build that would absolutely benefit from an x-pipe exhaust system. It will definately be a low rpm torqemonster type build which is what you want anyway given that it will be more of a cruiser and fuel economy is an issue. Something in the 230-240*@.050 on a 112*+ LSA should be in the "ballpark" i would think. 


The stroker i specced for Mike (MFR426) would easily run that number in an a-body :

http://www.dodgecharger.com/forum/index.php/topic,43911.0.html



Ron

[Charger-Bodie]

Why are you so against headers?.......I had an A-body a couple years ago with a 69 440 in it, I ran the schumaker mounts and tri-ys with a column auto. ZERO clearance problems anywhere........I did run manual steering though, so Im not sure on the power set-up.

[375instroke]

Well, it appears you have done your homework and are top of things ! 

Thanks.  I've done a lot of reading and parts collecting, but not much doing.  If I could get the parts on the car faster than they get stolen, I may get somewhere.

Looking at that pic of the engine on the stand you can see how pinched that driver side manifold is to allow for steering colomn clearance. The other pic illustrates how close the master cylinder the manifold is....i would be concerned with radiant heat and brake fluid boiling. Perhaps the M/C could be relocated ?

The A manifold is out of the question.  I don't remember the B manifold being that close on my friends '67 440 Barracuda, and he never had any problems in SoCal summers, but yes, that is close.  I'll be using a 400 block, which will add a bit more room.

What do the guys on BB Dart say about HP/TQ numbers with these manifolds ? Has anyone actually dynoed an engine and experimented with different cam profiles to see what works and what doesn't ?

I don't know anyone using the stock A manifolds on transplanted motors.  They all use B manifolds or headers.

As you probably know those engine simulation programs are often unrealistic. Real world numbers are often quite humbleing. I can assure you that none of the max effort FAST (Stroker) builds with lots of compression (13:1) using fully scienced out heads and the higher flowing B-body HP manifolds make the kind of power shown in your manifold simulation program. 

Why are you so against headers?.......I had an A-body a couple years ago with a 69 440 in it, I ran the schumaker mounts and tri-ys with a column auto. ZERO clearance problems anywhere........I did run manual steering though, so Im not sure on the power set-up.

Here's an example of why I don't think I need headers:  Scott McKenzie's 11.76 @116 MPH 440 Six-Pak Roadrunner  Here's his specs:

• WEIGHT- RACE TRIM 3940
• ENGINE-440CI - STOCK STROKE
• PORTED 906 HEADS
• STOCK INTAKE
• STOCK EXH. MANIFOLDS
• TTI EXHAUST 2 1/2 X PIPE
• DYNOFLOW MUFFLERS
• COMP-11 T0 1
• DIAMOND FLAT TOP PISTONS
• EAGLE CRANK
• HYD CAM

So, I'll have an advantage of lighter weight, better tires, probably better flowing heads with a closed chamber, probably a higher flowing intake, and more cubes, and he's already into the 11s, so regardless of what the engine sim says about power, it's been proven that the iron manifolds don't necessarily make your car slow.

I realize this is not a max-effort build so i guess the only answer really is to build it and live with the results....whatever they may be. 

Yes, this is true.  I just don't want a turd, which is what I've seen before from people just throwing parts at a car.

Honestly, mid 11's in an a-body should be a cakewalk, even with a crummy exhaust. The cam will need to be ground on a wide LSA to reduce overlap and help with scavenging. This is one build that would absolutely benefit from an x-pipe exhaust system. It will definately be a low rpm torqemonster type build which is what you want anyway given that it will be more of a cruiser and fuel economy is an issue. Something in the 230-240*@.050 on a 112*+ LSA should be in the "ballpark" i would think. 

Don't get me wrong when I talk about fuel economy.  I'm not looking for 20MPG.  I've just seen cars that cruise at 3500RPM, or have a huge cam that's dumping raw gas out the tail pipe, or no vacuum advance, and that's just stupid to me for a daily driver.  I'm just wondering, since I'll have a .69:1 overdrive, would I be better off with a smaller motor, since I can run lower gears, and have the overdrive to drop me down while cruising?  I'll play with the sim some more to see what a 470 and 451 do to the power curves.  I played with them before, and found that the HP was the same, just that the torque curve was moved down and to the right, compared to the bigger motors, which is what one would think.  I'd definitely run the 512" motor if I was running 2.76 gears, or something like that, but with the OD, I need something like 3.91 or 4.11 gears, or else the RPMs drop to incredibly low levels.

[Mike DC]

 

more torque = more gas consumption.

I don't think any amount of powerbands, gears, forced induction, camming or anything else can truly cheat this one. 

[375instroke]

More power does mean more fuel is being converted into energy, but a high HP motor is usually more inefficient at converting that energy into power at lower RPM.  A motor that makes more torque down low may be converting that fuel into energy more efficiently, and less of it is going out the tail pipe.  While at WOT, lots of fuel is going to be used, of course, but at part throttle cruise, a high torque motor can usually meter fuel more precisely, there is more vacuum, causing the fuel to vaporize better, and there is less CFM going through the motor at lower RPM.  Ever see a car with a huge cam, with very low vacuum?  Either the power valve is too high, and it starts opening at part throttle, or it is too low, and the jets are enlarged to make-up for the needed fuel, or other Band-Aid that dumps too much fuel at the wrong time, washes the cylinder walls of oil, and drops fuel economy down to 6-8MPG while putting around.  Another poor decision is ditching the vacuum advance.  It does nothing for power, and race cars don't have it, right?  See where I'm coming from?

[375instroke]

I think that I've changed this to a 470" stroker.  Better rod ratio, a bit more piston skirt, a bit less torque, a little shift in the power curve to the right.  Perhaps a little more balanced and streetable.  Still have no idea on what type of cam to get.  Many don't like flat tappet cams because of oil issues.  Many say roller cams destroy springs, and the lifters don't last long either.  The dyno sims I've been running show the hydraulic rollers have an almost identical power curve to a similar size solid flat tappet.  What is it about the specs of these cams that may be throwing off my simulations?  Do the lash settings get figured into the duration numbers?  Dyno2003 takes the advertised duration numbers, like at .006" lift, and the .050" numbers, and computes the aggressiveness of the cam.  The hydraulic roller numbers come up to a lower aggressiveness profile than the solid flat tappet cam of similar duration, but I know that can't be true just by looking at the lobes.  Using the sim is a lot cheaper and easier than trying out a bunch of parts, but am I getting anywhere?

[firefighter3931]

I agree with the 470...that's what i would be using in an a-body. More room to work under the hood and slightly less weight on the nose of the car. A good hyd roller will make as much power as most streetable flat tappet solids but they won't rev much past 6k without valve float issues. As long as you build the engine combo with that in mind you will be fine. With a standard port intake window the engine will be all done by 6k anyway with 470 cubes.

The hyd roller works fine with mild spring pressures and you don't need a fully rollerized rocker arm to keep things happy. Crane Gold, Comp pro magnum or even ductile iron are fine.


Just for giggles try plugging this cam into your dyno sym but widen the LSA to 112* and see what happens. I like the holley street dominator on this type of build. A proform 750 dp'er (830cfm real world flow > measured) would be a good choice for the carb....smaller primaries for good fuel efficiency/strong vaccum signal + sharp throttle response.... and enough flow to keep it happy up top. If your heads flow in the 280-290 cfm range at peak lift this combo should make 540hp/600tq or therabouts. I'd be interested to see what your program says. 

Here's the cam specs : http://www.compcams.com/Cam_Specs/CamDetails.aspx?csid=648&sb=2



Ron

[firefighter3931]

The hydraulic roller numbers come up to a lower aggressiveness profile than the solid flat tappet cam of similar duration, but I know that can't be true just by looking at the lobes. 

It really depends on which cams you are comparing. Most off the shelf cams use milder lobe profiles. The really good stuff  appears in the master lobe library and you have to know what to look for. 


For example : the Comp XX and SQ lobes are based on an agressive .875 lifter profile and will show ramp speeds approaching if not surpassing many hyd roller grinds. Jump up to the .904 lifter MM lobes and it gets real agressive....more ramp speed than many solid "street rollers". 

A good option with the solid flat tappet cams are the new EDM style lifters that feed pressurized oil to the cam lobes....much better than conventional splash lubrication. Some guys try to cheat it up by using a higher rocker arm ratio to increase lift and lifter velocity but this can cause valvetrain stability problems at higher rpm's. The spring pressures required to maintain valve control often exceed the safe limits of flat tappet cam territory. The right thing to do is use a 1.5 rocker if this is going to be a street type build that will see lots of idle time and low speed operation. At least that's the way i see it. 


Seeing as this is a fresh build and you are starting from scratch....the hyd roller is the logical way to go, inmho. The roller will have better "high lift area" under the curve and increased duration past .200 lift. This is why a roller typically make more torque than a conventional flat tappet....assuming similar seat and .050 duration #'s. 



Ron

[375instroke]

The sim likes all the cams in the 280deg. range.  Anything above and below shows less power.  Here's the XR286HR hyd. roller on 112 and 110 stock lobe centers, along with the 280 on 110 and 112.  If I had my way on the intake, I'd use this, but its made in RB form only.  Here's a motor with a big roller cam using it, and an intake shootout:
Mopar Muscle Mauler 440 Engine Project
Mopar Engine Intake Manifold Comparison

[firefighter3931]

Those #'s seem low with a 470ci build and descent flowing heads 

The ICH dual plane is an excellent piece.  Your best bet is still going to be a lowdeck street dominator, inmo. It's moves enough air to make 550hp and possibly more. On a build like yours i would be expecting power numbers similar to General 01's lowdeck stroker. Check it out in the proven combo's section.


Ron

[375instroke]

I ran General_01's motor through Dyno2003, and compared it to my 470 with the 280 hydraulic roller and manifolds.  I'm assuming large tube headers for his.  Is the Street Dominator a single plane?  That's what I used.  I see it in dual and single plane forms, but only single plane for Mopars.  Does that thing have an EGR provision?  His motor came out lower than the actual dyno chart.  The torque and HP peak RPMs came out dead on, though.

[firefighter3931]

The SD is indeed a single plane. I did recommend a 1in open spacer to increase plenum volume on Generals build. The old school street dominator is one of those anomolies....it doesn't look like a bad azz manifold but it allways performs like one on any dyno test i've seen. 

I'm not sure what General was using for headers on dyno day but he does have a set of 1.75in small tube headmans that will be used in the car.

Maybe try plugging the same combo (yours) and substitue a header for the HP manifold and see what happens.




Ron

[375instroke]

With this motor, I'm going to have a lot of torque.  I ran the numbers through Drag2003 with a 727 and 2.76 gears, and come up with the same times as an A-518 and 4.11 gears.  I'll run about 11.7@122 and cruise at 2200RPM@60 and 85@3000RPM.  Why hassle with the overdrive when I don't see much advantage?  Looks like I need a new project for a big block A-518.

[Ghoste]

11.7 with 2:76 gears?  That will be very impressive.

[375instroke]

That's what the program says.  Don't forget, most say "Good luck getting it to hook."  With the higher gears, there will be less torque to the ground due to the lower torque multiplication, and the stroker would have gobs of that to go around, and it would start as soon as you turn the key.

[Mike DC]

           

The phrases "it can hook all that power up" and "it's a streetable cruiser" tend to be inversely related.




I think trying to hook up a big-torque stroker motor in a streetable & heavy B-body is a pretty thankless job.  I'd rather just have the motor inside a lighter weight car and not be breaking parts all the time.  Not to mention the practicalities of cramming HUGE rear tires into a cruiser.

Just my two cents.