400 with Speedmaster Dyno Results
 

Just thought I would post the results of a recent dyno session. It is a .040 400 with Icon flattops, Eagle rods and HR cam. The Heads and cam were bought from Pontiac Speed Shop. All pulls were made with a 770 Street Avenger
carb. The sheet posted was with a TII and a 1/2" Super Sucker spacer. We tried an RPM and it made as much HP and a little more torque but it took a 1" spacer and since I am putting this in a 79 TA that won't work very well if. Peak numbers were 434 HP and 458 TQ. I was told this was a conservative Stuska Dyno.

Run the better intake with a drop base air cleaner. It looks better, and turns your shaker into a functional cold-air intake.

Nice numbers for a 400!

https://butlerperformance.com/i-3164...tegory:1234772

So does that mean you run out of the box speedmaster alu heads..?

Yes, no porting but Randy setup the springs for the cam. Also, this was with 32 degs total timing.

Wow, that's nowhere near enough timing.
It's got to be a combination of frustrating and encouraging to get a good dyno sheet but know that a whole bunch of power was left on the table with a simple adjustment.

What compression ratio?

Not sure about that, the KRE d-ports do not need a lot of timing.

Good numbers, I think it could use a little more cam.

Good numbers and the Speedmaster heads seem pretty capable as it didn't need a lot of cam either.
/
Way back when the KRE's first came out a 400 build made right at 450hp with the 221/229/112 Crower cam about 10 more HP with the 228/235/112 cam. Torque peaked in the 460-470 range. They didn't like much timing either, right around 30-32 degrees nearly as I can remember......

I must be honest by saying that I am not impressed!

Here’s a dyno test of a 364 cid SBC with Trickflow heads that I ported up to 260 cfm.
The motor had 10.25 compression and a Crower cam.

Two flat tappet hydro cams where tested .
The final cam as used in this test made 9 more ft lbs of torque and 17 more hp.
The cam specs where 220/226
Cam Lift .462” .470”
1.6 rockers where used and the cam was advanced from 112 to 109.
A 700 Holley was used on top a Victor jr manifold that I had blended the plenum on and gasket matched,

I thought we decided comparing results from different dynos was “iffy” at best. Maybe I misunderstood.

Murf


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Not if in both dyno test being compared the correction factors are clearly stated and realistic and using the BSFC and fuel poundage per hour numbers match up with the uncorrected hp numbers , in which case yes, they can both be directly compared!

Steve,
What kind of dyno was that?

Stan

The other dyno sheet had none of that. Your dyno sheet has fuel in GPM while BSFC is in Lbs. One would at a min need fuel SG.

Stan

lose that street avenger carb... bet a true double pumper or even a properly set up Q-jet would get much better numbers (& mpg with the q-jet) with everything else the same.

Will be a really really fun car to drive now.
Was it dyno'ed with Headers or R/A manifolds or StockLog manifolds ?

Guessing you picked up probably at least 35-45 extra horses versus same build with un-touched Iron D-Ports.

i think thats about the power range of a fairly well prepped RamAir IV engine.
If it has good driving manners with street gears i would be real happy with it.

Stan the dyno test was done on a inertia type dyno with a capacity of 2500 hp as I recall.

400 with Speedmaster Dyno Results
 

Edited my post, as I miss read the dyno sheets.


Don’t know, seems like a nice build for a driver to me.

I think the RPM & Qjet would be a good set up though.


Murf


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I think you did good so congrats!

Few years back I had built & dynoed a 69' T/A RAIII 400 with stock iron heads, 10:1 CR & Lunati 227/233 cam and made 380 hp.

yes nice build for sure, my comment was only about the carb... im sure it will work ok but they dont get very good reviews & a correct Q-jet set up right would run much better. probably fit the shaker better too.

i had one of the 770 street avenger carbs, was brand new & came on a stroker motor i bought, they guy bought it because it was shiny & looked cool... i sold it to a friend who used it on a aluminum head stroked ford, the shop that built the engine said it was horrible to get running good on the dyno & they had to rebuild it to get it to run decent & even then suggested he find a different carb to use.

He put a engine together with out of the box parts compared to your hand ported heads and intake and made 17 less hp I think he did pretty good and with some fine tuning could have beat the numbers you came up with. They never even changed timing that could have been the difference right there. JM2¢