GetaZforgetGT

I have been looking at different pistons to go with for my desired out come and have talked to a few manufactures about their pistons. Right now it’s looking like JE is the route I’m going to go. I was going to use SRP pistons but they are only rated to a max of a 200 shot of nitrous and I don’t want to be at the very raged edge of what I plan to run. The JE are rated up to 250 so my 200 shot shouldn’t push it.

So here the idea.

58 CC Chamber
5 CC Piston Relief
.039 Gasket Thickness
4.035 Gasket Bore
4.030 Cylinder Bore
Piston in the hole .010
3.75 stroke
6 inch rod
233/239 cam that has a IVC of 45 so (289-233/2)+45 = Advertised Closing of 73

This give me 11.7 SCR and 8.69 DCR.

Is a quench of .049 going to be about right or should I drop it down to .039 by zero decking the block?

Problem is that running a zero deck on the same setup puts my SCR to 12.01 and DCR to 8.92….seems like I might be pushing it for my expertise level of tuning.

For that matter am I silly for leaving the piston in the hole and not going with a different piston all together to achieve the desired CR, DCR and Quench.

BTW, I have an electric water pump and 160 deg thermostat for added info on my quench question.

Any suggestions or insight?

Compstall

Send "Twofast4lv" a PM. He'll get you in the right direction.

1racerdude

Your gasket probably WON'T be 4.035 more like 4.100-4.125 unless it's a Cometic $$$$$$
.039 quinch is great-Fel Pro gasket.
8.92 is OK for DCR on pump gas-let a pro tune it.
Call Probe Industries about pistons,they are good quality and good price.
When ya figure in your correct number's AND advertised cam duration NOT@50 ya probably won't be that high on DCR.

GetaZforgetGT

I figured my IVC the way that SStrokerAce described a while back.
(Advertised duration - actual duration)/2 + ABDC = IVC

(289-233)/2 + 45 = 73
What did I do wrong?

No user Twofast4lv on this site.

I'll check into Probe.

BTW if I zero deck the block will my intake need to be worked to fit the setup.

Thanks guys
Any other advice?

Compstall

I see. Looks like he had it deleted. His other username on here is Oneflyn95Z28. Either way looks like these guys got you squared away.

1racerdude

It's best to call the cam maker or get it off the card. Sometimes that math only gets ya close.
Yes on the intake.
Ya can get Probe to make ya a set of pistons to bring it to zero without decking.

GetaZforgetGT

I'll take a look at my cam card later tonight.

Getting Probe or anyone for that matter to make me a piston for that is a good idea.
I'll just have to get the block prepped ahead of time so I will know what my final deck height (in case it needs more than a resurface) will be before I order the pistons.