Hey guys, I've been attempting to map out a 402 setup and "possibly" running my current ETP215 heads at 59cc with .040 gaskets.

Here is my dilemna:

402 with -12cc pistons/ETP @ 59CC/.040 Cometic/G5X4 net me:11.56(scr)8.67(dcr)
402 with -10cc pistons/ETP @ 59CC/.040 Cometic/G5X4 net me:11.84(scr)8.87(dcr)

I do live in south Florida where it does get hot, but we are close to sea level and we always have 93 octane. This combo will go into a 02' ZO6 and it is not my daily driver.

What is everyone's opinion on Mahle pistons versus Diamond?

TIA!
Alan

 

pick either one, as long as you got a good tuner, don't worry about it, but always remember to put good gas in her. more compression makes more hp. as far as pistons, i like them both. can't go wrong with either one. but, the mahles should make a little more power over the diamonds on an engine dyno test.

 

+1 you will need a good tuner and you should be fine.

 

Thanks for the help guys....I always thought diamond was a better piston..

Anyways, take care!

 

Alan,
Are you using the PianoProdigy calculator? According to that one, I have 11.36:1 SCR and 8.97:1 DCR. The big question is why not sell the ETPs & FAST and go with a L92/L76 topend?

Rob

 

Yep, PianoProdigy's calculator...

I've checked it several times.

I thought about doing the L92/L76 but trying to find a buyer for high dollar parts used is difficult. I did place an add on here and CorvetteForum and have had very few responses(1 on here and 0 on CF)....

I think my topend will work fine as many others have had great results with box stock AFR 205's! Plus, it's money I've already spent, therefore it's a little easier on the bank account!

Alan

 

Rob, Did you start with the LS2 sheet or the LS1?

I just double checked it again...my values are correct

 

Alan,
LS1 3.9" bore x 3.622" stroke.
I really think the 8 1/2 to 8 3/4 DCR range is ultra conservative for 93 octane, especially if your quench is tight.

Rob

 

Rob, the LS2 402 is a 4.0 bore with a 4" stroke and 6.125 rods....Start with PianoProdigy's LS2 sheet....

So, you think I should go with the -10cc psitons for a final DCR of 8.87 then?

Alan

 

I was saying that I've got 8.97:1 DCR in my LS1.
You shouldn't have any problem running 1/10 lower in your 402.

 

Just keep in mind that end of 07 year Federal legislation will be putting an end to 93 octane. States that do not enforce the measure will be losing their Federal funding in different ways. Don't count on always having 93. Just a heads up.

 

why does piano prodigies tool not allow u to punch in 6.098 on the rod heights or the -0.007 on piston out of the hole,it resets back to .001 and 6.1 on the rod height

 

I haven't heard anything about this. I tried to do a quick google search and found nothing either. Do you have anymore info?

 

It allows you to...it's just the number you see is rounded. If you don't want to see the rounded number, just right click on the cell and click "format cells" and change it to show three decimal places.

Hammer

 

Any links with more info would be appreciated. Im currently in a 93octane state

 

I see now,thanks....

 

I went with the -12cc pistons to keep the combo on the safer side....DCR will still be 8.67 with a SCr of 11.56. I think the car will still run great with this setup!

I surely hope the 93 octane thing is rumor!

 

I got the info from the Performance Shop Raylar. They deal with Mercruiser Marine and GM on modifying BBC marine motors. All their new motors being built are being a tad detuned due to the upcoming octane restrictions. As to when it will take effect I have no exact date but from what I was told it's slated for late 2007.

 

man i hope not. my car craves 93 oct

 

Time to start ordering Torco additive!

Alan