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Do the numbers seem low to you? 440-500in stroker

Started by 2Luke2, July 10, 2014, 05:52:46 PM

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2Luke2

So we took the car down to get some quick A/F numbers down on the dyno today and do some carb tweaking. We only got to make one pull before the dizzy broke. Though with the one pull we did get, we feel the numbers are a bit low. Just wanted some opinions to see if we are where we should be or just jealous of other people's numbers haha.

Below we listed our specs and some specs of a build in the proven builds section. We figure we are at 512hp and 498tq to the crank(which is being very generous to us) with the dyno numbers we pulled today on a chassis dyno before the dizzy broke. What we are wondering is if a port job on the heads and a cam would make 100hp or more of difference between the two builds.

Just for reference the chassis dyno with the altitude correction factor is reporting 410hp@5400 and 398tq@5250. We came up with the numbers at the crank by just adding a good 25% from the 727 drivetrain loss, which could be way off.

Just to put it out there after the dizzy broke the numbers literately dropped in half! I thought we broke something good haha, but we were glad to find out it was just the distributor.

So we have Hughes 505 stroker kit race balanced with .040 flat top pistons compression of 12.1:1... much lower dynamic compression if we did our math right and we are over 6000ft in elevation :)
4.36 bore
4.25 stroke
HE285HL hydraulic flat tappet cam - 241/247@110 .545 .545 with 1.5 rockers
84cc RPM Heads out of the box(60929)
Proform 950 Carb
Performer RPM intake
smithbros push rods
Johnson lifters
MSD 6AL2 box




We were comparing our setup to this:
511" stroker kit (440 block) with 10.7:1 compression
4.375 bore, 4.25 stroke
Eagle crankshaft
Diamond 13cc dished pistons
custom Comp Cam 245/257@110 .535/.542 lift with 1.5 Comp Cams Pro Magnum Rockers
Mopar aluminum straight plug design heads (Edelbrock Performer RPM's) with stage I port job by Porter Racing
flowing 280cfm @.600 lift
MSD ignition
Quick Fuel 850 cfm carb with 1/2" spacer
Holley Street Dominator intake
Melling oil pump
Milodon high volume water pump
Mlodon 7qt oil pan
ARP accessories

The build made 10 inches of vacuum @ idle (900rpm)
Using 93 octane...

Horsepower: 609hp @5400 rpm
Torque: 688 @4200 rpm

Kern Dog

We figure we are at 512hp and 498tq to the crank

My 493 with stock Edelbrock heads, the MP 292/509 cam and 2" Headers made 370 HP and 469 TQ to the wheels in 2005. I thought the numbers were a bit low but in reality, I've never heard anyone leave a dyno session feeling happy with their numbers.
Later I installed the Comp cam YOU have listed. The car didn't pick up much power but did idle better and had a little more mid RPM range power.

2Luke2

Well I wouldn't say we aren't happy with the numbers, but just wanted to see what people thought. All dynos and all engines are different so we don't expect to the same results. We just want to make sure we didn't screw something up. In the end the only thing that really matters is how we feel and the car is pretty nice for 6000+ ft elevation. Though it's nice to compare and hear other's thoughts.


BSB67

Quote from: 2Luke2 on July 10, 2014, 05:52:46 PM


HE285HL hydraulic flat tappet cam - 241/247@110 .545 .545 with 1.5 rockers
84cc RPM Heads out of the box(60929)
Performer RPM intake


custom Comp Cam 245/257@110 .535/.542 lift with 1.5 Comp Cams Pro Magnum Rockers
Mopar aluminum straight plug design heads (Edelbrock Performer RPM's) with stage I port job by Porter Racing
flowing 280cfm @.600 lift
Holley Street Dominator intake


Don't under estimate the difference these three things make. 

The 609 hp seems a little high.  I've seen this combo more than once in the high 500s.  However, if that was on Dwayne's dyno well...that's impressive.

And yours does seem a little down with all that said, but my guess is if after you get the dizzy right and put a good tune on it the numbers will fall in line.

You are very very correct in not getting to deep into comparing dyno numbers.


500" NA, Eddy head, pump gas, exhaust manifold with 2 1/2 exhaust with tailpipes
4150 lbs with driver, 3.23 gear, stock converter
11.68 @ 120.2 mph

c00nhunterjoe


1974dodgecharger

Quote from: c00nhunterjoe on July 11, 2014, 06:00:45 AM
Put it in a car, get a 1/4 mile mph reading.

I agree....in the end its what it can do on the street vs Dyno unless one was only to leave car on Dyno forever.

firefighter3931

Luke,

Don't place too much weight on the chassis dyno numbers....some read low and others read high. Chassis dyno's should be used to dial in the ignition and fuel curves and nothing more.  :yesnod:

What was the torque peak and at what RPM ? It should have been at peak tq around 4000 rpm or so.  :scratchchin:

With unported stock RPM heads that combo should be in the 550hp/600tq range (at the crank) no problem...at sea level  ;)


Ron
68 Charger R/T "Black Pig" Street/Strip bruiser, 70 Charger R/T 440-6bbl Cruiser. Firecore ignition  authorized dealer ; contact me with your needs

2Luke2

Thank you everyone for the comments. We definitely don't care that much about the numbers, but it's hard not to ask the question after you see and compare to similar builds.

We actually ordered a new dizzy because it will be here today. We are also ordering the replacement parts for the other dizzy so we will have an extra on hand in case this happens again.

Ron, one of the biggest reasons we asked was because the tq seemed very low. To the wheels with sea level correction we were only seeing a max of 398.81tq to the wheels around 5250. After that it started to fall off. We thought if anything we should see a pretty decent tq number, but when it was below 400 we started wondering. Even if we gave it 25-30% drive train loss that only brings it up between 498-518 to the crank. So missing 5-25tq by comparing similar builds is totally understandable, but missing close to 100tq seems a bit off. So that's the main reason we posted. Even though she runs pretty good maybe we rounded off a lobe at break in or something, but we don't know so we ask the question. :)

Either way thanks again guys! Your help and comments is always appreciated!