pistons

[BigRedTrucker]

Are these pistons any good: http://store.summitracing.com/partde...0&autoview=sku

I can only tell a 1cc difference and a weight difference (plus $100) between this one: http://store.summitracing.com/partde...0&autoview=sku

I emailed summit but they didn't know anything besides maybe the one that is cheaper was more popular causing the per unit to drop. I'm trying to get my compression down to 9:1 so's I can use regular gas. Also, is a onepiece rear main seal externally or internally balanced? Pretty sure it was internal.

I got vortec heads and I was wondering if the exhaust manifolds off my 305 would fit?

TIA

[thesals]

they're both speed pro pistons the only difference really is the dish volume..... either way i'm not very fond of Hypereutectic pistons... they're known to fragment from detonation.... what motor and setup are you using that you need a 10cc dish to get down to 9:1 comp??

[BigRedTrucker]

I'm running 64cc vortec heads. speedpro says with 64 cc heads, their flattops with 4 valve reliefs with 5cc piston head volume give you 9.34:1. I don't plan to do too much but I'd rather not have noise at startup.

[76GMC1500]

Hypereutectic pistons are only more prone to failure when compared to forged pistons. The trouble is, the prices don't compare. Go ahead and run the hypers with confidence. All of the major auto manufactureres are using hypereutectic pistons in most of their engines. I'm running Keith Black hypereutectic pistons in my 350 under a pair of Vortec heads and 9.25:1 compression. I estimate the engine makes over 300 hp at the crank and runs on 87 octane. Run your ring gaps loose.

You may want to double check your compression numbers. I'm running a 12cc dish and came up with 9.25:1 compression. You need to know your head gasket thickness and deck clearance to get an accurate compression ratio number.