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502 with Afr heads ideal compression ratio

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502 with Afr heads ideal compression ratio

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Old 12-30-2014, 04:05 PM
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Default 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!
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Old 12-30-2014, 04:22 PM
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If it were me 9.5-9.8:1 and a cam that wasn't designed for crap heads 20 years ago
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Old 12-30-2014, 04:39 PM
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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.
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Old 12-30-2014, 04:42 PM
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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.

Last edited by mike tkach; 12-30-2014 at 06:33 PM. Reason: more info
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Old 12-30-2014, 05:52 PM
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Originally Posted by Satisfaction
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!
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Old 12-30-2014, 05:55 PM
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Originally Posted by lil red
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.
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Old 12-30-2014, 06:01 PM
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EFI or carb ?
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Old 12-30-2014, 06:13 PM
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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 $$?
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Old 12-30-2014, 06:15 PM
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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
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Old 12-30-2014, 06:32 PM
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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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