552 Dyno Day

Got my 552 ready to go up to Twin Falls, Idaho for Dyno next Thursday. Hoping all goes well, have had troubles with rod bearings lately. This is C9 block, scat forged crank, P51 heads (ported) with 2.30 intake valves and titanium retainers for the 1.64" springs. 280* intake duration, .796" ish lift Intake, 300* exhaust (small 2" headers). Crower 1.73 rockers, topped with mafia intake and 1150 cfm carb. Kaase oil pump, with bigger oil pickup tube. 14.4 compression. Also have Jomar cone spacer with 3/4" open spacer. Many thanks for all the help with this motor!

Hoping for 900 to 950hp range. Dyno is at 3730 ft. elevation

No disrespect, im guessing closer to 800 due to altitude its costing roughly 100-110 horsepower at that altitude, and those headers seem a little small.

Yes, you are correct, we are normally around 13% ish less hp here due to altitude. (I'm even a bit higher at around 4400 ft where I live) I was thinking in low altitude terms...ha ha

Sounds like a fantastic build.
I am sure you will come close to or meet your goals.

I would also assume the dyno output would be corrected HP and Tq.

Cheers!

Ran the motor today, no problems, seemed to run fine. Oil filter was clear of any metal particles. Made 908 hp running these pretty small headers they had, my headers wouldn't bolt up with dyno stand. The port size looked like only 1 7/8" wide ha ha. Went up to 93 jet and 29* timing. 112 fuel.

Congrats nice numbers!!

Awesome!!

Were you running a vacuum pump?
Intake manifold otb or ported?

I am sure there is more in the combo! Well done.

bad ass #s
looks like a great build

whats it going in ?

Thanks for the kind words guys. Here is a little more info on it. No vacuum pump. Mafia intake, just cleaned up runners and plenum, port matched the very top of manifold about 1/8 to 3/16" to match up to head. torque peak was at 6100 rpm, 742 lb. ft. 900hp at 6500 rpm, going steadily up to 908 at 7200 rpm. Held 50 to 60 oil pressure with the full groove main bearings and kaase pump. This is my third solid roller motor, the other two had rod bearing issues, that's why the full groove main. (had to buy two sets of 1/2 groove) Going into my '69 Mach 1, been hashing on it with various motors since 1982!!!!! ha ha

Will try to post a dyno sheet later on, but torque was 735 at 5400, 737 at 5600, 737 at 5800, 741 at 6000, 742 at 6100, 737 at 6300 731 at 6400. Within 12 lb. ft. for 1000rpm range

glenevans wrote:Will try to post a dyno sheet later on, but torque was 735 at 5400, 737 at 5600, 737 at 5800, 741 at 6000, 742 at 6100, 737 at 6300 731 at 6400. Within 12 lb. ft. for 1000rpm range

Please do post the dyno sheet.

Trying to post pic of dyno sheet from phone, keeps saying file is too big.....but says "0" mb size ????

Thanks Paul!

IMO the reason why it flattened out from 6,500 to 7,300 rpm is because those headers are too small and were a real bottleneck restriction to the engines ability to breath. I wish you had a set of my Chevy header adapters on those ports and then borrowed some 2.250" BB Chevy headers to bolt on it while it was on the dyno. Then the exhaust would not have been a restriction. This in turn may have called for some jetting changes or different carb tuning.
Charlie

c.evans wrote:IMO the reason why it flattened out from 6,500 to 7,300 rpm is because those headers are too small and were a real bottleneck restriction to the engines ability to breath.  I wish you had a set of my Chevy header adapters on those ports and then borrowed some 2.250" BB Chevy headers to bolt on it while it was on the dyno. Then the exhaust would not have been a restriction. This in turn may have called for some jetting changes or different carb tuning.
Charlie

YEP ... unless he wants a wide range abundance of mid range torque ... the headers need to be larger.

I will probably try some adapters. How thick are they?

They are wedged shaped in trms of the side profile and go from 5/8" to 7/8".

I do think that Glen's engine should have a bigger primary tube but....

J.Y. Kelly's 562" P51 did this...

950.6 @ 6,700 rpm
950.6 @ 6,800 rpm
951.3 @ 6,900 rpm
950.7 @ 7,000 rpm
I wish it had been pulled higher...this was a decade ago.
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Chris S. 588" engine four years ago.

1,017 @ 6,600 rpm
1,018 @ 6,700 rpm
1,019 @ 6,800 rpm
1,018 @ 6,900 rpm
1,017 @ 7,000 rpm
1,018 @ 7,100 rpm
1,014 @ 7,200 rpm

Seems like the power gets there and holds on. Both had unported 'Mafia' intake manifolds.

If these engines had a typical ported Victor manifold the HP would have been in the shitter at and beyond 7,000 rpm.

Got the header adapters today from Charlie Evans (thanks), hope to do some additional testing with 2.25" primary tube headers soon. Very nice looking!