Need help deciding on stall speed

[fizz]

I am building a 493 stroked 440 six pack 1970 charger. Original plan was wait until dyno testing complete but out of time if I want to get in a shake down drive before winter. Trans is a silver sport(previously kiesler) overdrive automatic with a lock up converter. They custom build the converter, and I need to pick a stall speed to complete my order and get the trans here about the same time as the motor. Expecting probably just under 600 hp and just over 600 torque. TTI 2" headers with TTI 3" exhaust. Plans for the car are power tour type driving. Engine is supposed to be built accordingly. Havn't picked the rear end ratio will do that after I get a feel for how the car drives but currently 3.23. Engine builder thought 3500 stall but seems high to me. He is supposed to be sending me a dyno sheet from a similar build. Any help with stall speed or how to pick it off the torque curve on the dyno results would be appreciated. I can live with a lower ET to get more drivability. Sorry, I don't have the cam specs, but I suppose some speculation can be made from the hp,torque targets. It is a roller hydraulic.

[firefighter3931]

The cam specs and engine's compression ratio will be needed to make a proper recommendation. The dyno results are the beast way to select a converter but in their absence the cam/compression ratio will get you close. 

Is the cam a custom grind or something off the shelf ? The engine builder should have no problem giving you the required details. 


Ron

[fizz]

 cam specs

[BSB67]

In my humble opinion, your cam does fit real well with touring goal/plan.  But everyone's tolerance for rumpity-rump is different.  3500 is probably about right.

[John_Kunkel]

Regardless of the stall speed, when the converter locks, your final gear ratio is gonna determine the drivability. With a 3.23 axle ratio, OD and a lumpy cam, you're gonna be lugging the motor at 40 mph.

[fizz]

Gear ratio is subject to what works as long I can cruise interstate. I picked what I believe is a reputable mopar engine builder, gave him some parameters, and let him build it. I suppose if I tried to bake my cake and eat it too, I get too live with it. Dyno numbers seem to get too important, rather than function. But, you guys think that cam is way off base?

[firefighter3931]

The cam is not overly large for the displacement but it is "healthy" 

Drivability on the highway will be fine....the engine will smooth out at 2000 rpm and cruise nice. Peak torque should be in the 3800-4000 rpm range depending on a few factors like the intake manifold, header primary tube diameter and cylinder head port volume. A dual plane will bring the tq peak in a bit earlier vs a single plane. On a cruiser type build with low speed throttle response a priority the dual plane is your best choice. 

I'd call Lenny at Ultimate converters and outline the combo and see what he comes up with for a converter. I'm thinking like Russ (BSB67) that 3500 stall is in the ballpark. 



Ron

[fizz]

Heres what I understand. Shift points and lockup with this transmission are programmable, so I can adjust to where the engine is happy. Torque converter they deliver with this transmission he said is a 2800-3700 stall depending on torque applied. So if I am snorting around, car will be more hotrod acting because of the higher stall converter. If I am on the highway, converter will stall sooner and lock up so cruises the highway well. If I get on the gas torque converter will unlock and back to hotrod. Gearset is likely too high @ 3.23 so need to change rear gears. 3.71 gives 80 mph @ 2500 rpm and 3.91 gives just over 75 mph @2500 rpm, either which I think would be acceptable. Am I offbase? What gears do you fellas think would be more appropriate with this build?

[John_Kunkel]

I think an axle ratio in the high 3's would be more appropriate. Even though a nominal 320° duration cam might "clean out" at 2000 rpm it's still gonna be sensitive to load (like climbing a freeway overpass) with a 2.40 final gear and lockup.

[firefighter3931]

I think an axle ratio in the high 3's would be more appropriate. Even though a nominal 320° duration cam might "clean out" at 2000 rpm it's still gonna be sensitive to load (like climbing a freeway overpass) with a 2.40 final gear and lockup.

That's a very good "real world" assessment  

The idle will clean up close to 2k but it won't be in peak volumetric efficiency until much higher. I'd shoot for 2500rpm cruise engine speed and gear it accordingly. When climbing steep grades you can allways pull it back a gear to keep it from lugging.  


Ron

[fizz]

Thanks for the help. I'm going to rebuild the rear end and install 3.73 gears.

[Challenger340]

256* @ 050 duration on 10.25:1 Static Compression Ratio ?  88* closing ABDC ? is that correct ?

IMO, this engine won't like much "load" below 3K rpm even with the big arm ? 
and,
Not really mid 2000's "cruise" rpm friendly , again "IMO".

[fizz]

I am dependant on my engine builder, didn't try to tell them how to do their jobs. They are pretty well known for Mopar engines. I guess the worse that can happen is a cam change. Dyno test Wednesday morning 8:00 am. I will be there. Any advice?

[fizz]

Crane tech agrees with you guys. It might not like mid 2000s. Said 500 inch engine might be ok though. Option will to be to program lock up and shift points up a little higher, maybe I should be looking at 3.91 gears. It is a custom grind.

[BSB67]

Crane tech agrees with you guys. It might not like mid 2000s. Said 500 inch engine might be ok though. Option will to be to program lock up and shift points up a little higher, maybe I should be looking at 3.91 gears. It is a custom grind.

You don't have anything that can't be undone.  Try it and see how it goes.

[firefighter3931]

Crane tech agrees with you guys. It might not like mid 2000s. Said 500 inch engine might be ok though. Option will to be to program lock up and shift points up a little higher, maybe I should be looking at 3.91 gears. It is a custom grind.

I would definitely go with the 3.91 gears or maybe consider 4.10's 

My old 10.5:1 440 had a 264@.050 solid flat tappet cam and it ran fine at 2500 rpm. This is a bigger cam that you'll be running in an engine that was 50 cubes smaller than yours. The extra cubes really eats up cam duration and tames down the manners. It'll be fine in a 500in build....inmho   

Is the 2500 rpm ideal....no, but it's an acceptable compromise. 




Ron

[fizz]

Dyno Results

[fizz]

Engine dyno yesterday. They delivered pretty close to what the promised, and per price quoted. Interestingly, with a stock used distributer on a MSD box I made comment the comment I was going to replace it, dyno operator liked the advance curve and said why screw with it. I don't understand why they didn't spend my money. Anyway, comments welcome, especially as far as the rest of the build to match up with the engine.

[Challenger340]

Looking Good 

What Heads ?

[fizz]

Ported stealths

[fizz]

So I am adding to this thread because it has the cam card and dyno results in it. Had three goes at adjusting lifters and still noisy(like a cold solid lifter) Used crane specs for cam position and comp specs for preload. Crane said this cam would be quiet with their lifters. engine builder installed comp lifters because ordered crane cam and lifter set, cam came without lifters because they were on backorder (I can get crane lifters maybe next week). Has PRW stainless rockers, which I don't like because there is no consistency at all where adjustment screws end up after adjusting lifters(from one intake or exhaust to another one may be screwed in or out several turns different) I realize that doesn't make any difference once all are adjusted, just seems like a sloppy manufactured part. Engine builder says cam is aggressive, run it for a while, noisy is OK. When setting timing with a vacumm guage needle jumps about 2# at idle(1000 rpm). Cam is lopey, so maybe that is OK.
SO, options:
1: Order crane lifters and give it another go
2: Order crane lifters, rockers, push rods as a matched set
3: Order everything including cam in another grind
4: Run it
Engine is a 500 cube 440 stroker with a six pack, 2" tti headers and 3" exhaust, Firecore dist. with revenator box, ported stealth heads, overdrive auto trans and 391 gears.
This isn't a drag car, I want to drive it, don't want a slug either.
It isn't about trashing my builder or money, I just want it right.
I have a good mechanic(diesel) who works for our business to help. This is out of our league, but we can follow instructions.
Thanks in advance for any help

[Kern Dog]

The transmission that you have is a later, updated version of the GM 700R4. First gear ratio is 3.06. It seems that you won't spend much time in first gear with the 3.91 axle ratio. I saw that the Firefighter guy suggested a 3.91 or a 4.10. I can't even imagine running a 4.10 with this trans! 20 feet out of the hole you'd be in 2nd gear!
I ran a 700R4 in a 76 Camaro with 3.42 diff gears. It was a great combination for a small block Chevy that needed to rev to make power. The .70 gearing of the overdrive in a 3.91 results in a 2.73 final drive. Nice.

[cdr]

I have a solid flat tappet Howards cam in my 512, 248@ .050 in & ex, 110 lobe sep, also have overdrive .69, with lock up, any thing below 2000 rpm i can not use the lock up converter, i had 3.91 gears, but now have 3.23, I like it MUCH better with 3.23, has plenty low end tq to pull overdrive at 2000 rpm & up.
I also have the big indy single plane intake & i have max wedge ports.

[fizz]

Well, pulled the trigger. Out with the crane cam, comp lifters and prw rockers, in with a lunati roller and Harland sharp rockers