I recently bought a 95 Z28 with M6 with a Powerdyne that according to the previous owner has a 9psi pulley on it. it also has a what sounds like a broken piston (he claimed it was the water pump). i'm building a new short block for it with JE pistons # 203194 and matching JE file to fit rings # J100F8-4030-5, Eagle connecting rods # CRS6000B3D, and Eagle crank # 435334805700. Basicly it should bring me a compression ratio of around 9.3:1 with forged 6 inch H-beam rods and a 4340 forged stock stroke crank. i was looking at the comp cams 269HR-12 and haven't yet picked valve springs at this point. i haven't seen anyone on here listed with the powerdyne and a 9psi pulley even with a search, but any thought/suggestions would be welcome by me.

thanx

 

You may do better posting ifn "Forced Induction". Anyway, what are the cam specs? A 112 degree LSA sounds kind of narrow for a blower car.

Rich Krause

 

i thought about it, but i was hoping it may get the same responses in here also. as for the cam, i figured 112 is about as low as i'd go. i've done other blown apps with a 112 and it worked on them, but they weren't LT1's. what do you use?

 

I'd go with something a little higher than a 112 lsa. Be better for your boost anyhow.

 

any cam suggestions? open to idea's.

 

There's a huge number of variables in choosing a cam. But most LT1 blower cams are 114LSA, some as wide as 116 degrees. A combination of Comp Cams lobes #3190/3192 on a 114LSA works very well on many mild blower LT1's.

Rich Krause

 

i know my share of picking cams it's not my first venture at this. i don't think a 112 lsa is that unusable on a blown application although i agree a 114 would be more ideal for the set up. i preferr to keep them around 112-115, but i haven't found many at this point to my liking although i haven't seen many dyno numbers on similar boosted LT1's. i've ran accross some charts with boost, but not enough to show all of the veriables that i'm looking at.

 

now that i've looked again through the comp cams selection i can see i missed a few choices. the 218/230 .495/.510 114 is closer to what i was looking for but didn't see. thanx for pointing them grinds out since i wouldn't have went back and looked again otherwise. i like the duration intake/exhaust split much more on this one with it's overall specs being much closer to what i was looking for.