joey aucoin

I was just looking for any ones opinon on speed pro pistons . I have a 92 rs camaro w / a 355 , stock 76cc ( self ported heads ) , stock crank and rods . With the speed pro dome pistons (p.n. 844-8-kh618cp ) just hypereutectic w / moly rings . This combo will put me some where in the neighborhood of about 9.5:1 compresion . I don't mind that , I was just wondering about the quality of speed pro . Any one care to coment ? Thank you !

Apeiron

Speed Pro is just fine. Are you sure you'd be at 9.5:1 with domes though?

Mkos1980

iTrader: (8)

I run speed pro's and they have been good so far in my 383

joey aucoin

I am not 100% sure . That number was just figured up a few moments ago by a friend of mine and I . The heads are 76 cc but measured out to 81 cc using water .

shaggy56

I got 9.62:1.

That was with a 76cc chamber and .015 steel shim.

9.14:1 with 81 cc chamber

I averaged a .025 deck above piston but that wont be accurate unless you measure.

joey aucoin

I was just wondering what kind of speed pro ( w / what combo ) pistons you are using

joey aucoin

I was looking at trying to get any where beteen 9.5 to 10 so 9.62 that would be good too .

Apeiron

With a flat-top piston.

joey aucoin

I have .038 above piston deck . I was wondering were your heads a true 76 cc .
---------- I have .038 above piston deck w/ the flat tops in the car right now.

shaggy56

I was going off the data you provided. I looked up those pistons on the Federal Mogul website.

edit:Im sorry with the 81 cc heads I get 9.5:1 and a .015 shim gasket. I calculated wrong for the dome ccs

If it had been a true 76 cc then 10.03:1.

Apeiron

I think by .038 he's thinking of quench.

Irockz

iTrader: (1)

Speed Pro hypers are the only ones to use,IMHO.Much better quality that the KBs.

Mkos1980

iTrader: (8)

I dont know the number off hand but with a 5.7 Rod and a 3.75 stroke the 383 piston comes in around 10:4:1 with a 64 cc head. It has 2 valve relieves. I run the shortblock with a 219 cam and miniram. Plenty of track use and dyno runs and its all nice and good.

joey aucoin

I have 5.7 rods but only a 3.48 stock stroke . If I can get 9.5:1 I would be just fine with that . I was looking to use a comp 292 cam and I have 1.5 comp rollere rockers already . I know that may be too much cam . I was just going off of a combo my brother had and it worked out great for him ( 12.3 in a s10 ) . feel free to put in your two cents . Thanks for all the help.

Sonix

iTrader: (1)

might want to get your machinist to cc a chamber for you. I couldn't get a very accurate measurement on mine, but my machinist did a chamber or two for me while he had to do other work to the heads.

speed-pro hypers are good. Not a race only part (high $$), and not a cheapo factory replacement cast. Much cheaper than a KB piston, and IMHO, the same thing.

I've got the H345's in my motor.


the bigger the cam, (like a 292), the more CR you need to run well. I forget what the duration @ .050 is for that cam, but you do want to be close to 10:1. Are you considering milling the heads or decking the block? 81cc's just sounds huge to me. *IF* you had to get the block decked or the heads milled due to warped surfaces, might as well get them cut down a fair bit, get your moneys worth, then get flat top pistons.

joey aucoin

Hey man thanks for the info. I am currently looking into getting the heads milled , but my mechanic was showing me some dyno sheets that show going from a 9.9 to 10.5:1 is only about 8 HP . I dont know if they are 100% currect . I am still looking into it to find out more info . Thank you for you'r again for you'r help.

1989GTATransAm

iTrader: (3)

I just bought the Speed Pro forged pistons for my car. Look nice and came with the coated skirts. I think the Hypereutetics also come with the coated skirts for an extra bonus.

joey aucoin

What typ of set up are you using in the rest of the motor . I mean like heads, valves, cam ex.

1989GTATransAm

iTrader: (3)

See signature. Fixing to go higher in the RWHP department.