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Satisfaction 12-30-2014 04:05 PM

502 with Afr heads ideal compression ratio
 
I have a 502 gen VI short block with Srp flat top pistons(believe stock from GM)
That I am going to be building with 315 AFR heads and the crane 741 cam.

I believe the compression ratio will be 8.9-1 What is an estimate HP & torque this engine will put out?

Is the compression to low? Should I be boring the block .030 with more compression? or is that not needed?

8.9-1 sounds great for reliability purposes but want to make sure it will still put out enough power.

Thanks!

Unlimited jd 12-30-2014 04:22 PM

If it were me 9.5-9.8:1 and a cam that wasn't designed for crap heads 20 years ago

MILD THUNDER 12-30-2014 04:39 PM

Just get the 315 heads with smaller chambers to get the compression up a bit. Then go with a custom cam, with more lift, to take advantage of the 315's cnc flow capability.

mike tkach 12-30-2014 04:42 PM

i would go with 10-1 and a cam from bob madera,he also can get you a fair deal on the afr heads.650 hp is what i would predict.edit in,i just reread your post,imo the 305 would be a better choice for your application.

sutphen 30 12-30-2014 05:52 PM


Originally Posted by Satisfaction (Post 4241867)
I have a 502 gen VI short block with Srp flat top pistons(believe stock from GM)
That I am going to be building with 315 AFR heads and the crane 741 cam.

I believe the compression ratio will be 8.9-1 What is an estimate HP & torque this engine will put out?around 600hp

Is the compression to low? Should I be boring the block .030 with more compression? comps low,but if you have to order pistons,,just get the right dome for 9.5-1.right now you could run 89 octane

8.9-1 sounds great for reliability purposes but want to make sure it will still put out enough power.i've had great reliability at 10-1,but that requires high test.

Thanks!

answers in red

sutphen 30 12-30-2014 05:55 PM


Originally Posted by lil red (Post 4241876)
If it were me 9.5-9.8:1 and a cam that wasn't designed for crap heads 20 years ago

and yet it still works today.

F-2 Speedy 12-30-2014 06:01 PM

EFI or carb ?

Unlimited jd 12-30-2014 06:13 PM

Yeah it works, but the profile is way off for those heads. Why pay $450 for that when you can get something better for the same $$?

F-2 Speedy 12-30-2014 06:15 PM

Yup what he said ^^^ and a new dist. gear lol, custom grind is the way to go with those heads, Id bet it would make another 40 hp

MDGperformance 12-30-2014 06:32 PM

depends on what exhaust you are running,but lets say cmi elbow tops around 600,gil or stainless marine 580-590 that is what i am seeing on a fully dressed marine engine on my dyno,add a little more compression and play with some cams 30-50 more hp,just depends on were you want your power curve to be,the afr heads flow real well and don't need a lot of cam to make good power


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