Irocss85

iTrader: (1)

http://www.ryanscarpage.50megs.com/combos10.html

check out this site. combo #71.

Irocss85

iTrader: (1)

http://www.camaros.net/racing/SBCombo.html

here's another good site to check out.

69Camaro...

iTrader: (8)

Thanks! they were very informational. Lunati seems to be another good company of choice

speedy55

I say keep your 400 horse motor tha you already have and put an NOS powershot on top of it. An additional 125 horses when you want it!

69Camaro...

iTrader: (8)

no because i want my dads motor and he wants a better one

He spent 3 grand for his and im trying to build one lesser or equal to the same amount he payed for his. The vortec motors will not accept his old hilbourn fuel injection, so i made a deal with him that i would build him a motor

69Camaro...

iTrader: (8)

so im being told on my other forum that high lift cams should require a decent amount of compression. I'm about to buy these pistons, but must make sure they will work with my application. They say my comp. should be in the 9.6.1-10.x.x range, but im looking at a piston that has a compression around the 9.3.1 range. Is this going to hurt my chance in gaining horsepower because of low compression?

Heres a link to the pistons-http://store.summitracing.com/partdetail.asp?part=WIS-PT009H3&autoview=sku

I was then told this, which is another way of increasing your compression even though the piston claims 9.3.1 w/ a 64cc head.

"Using mathatic a 4.030 bore x 3.75 stroke cylinder holds 783.877cc's add 20cc for the dish 64cc for the chamber 9cc for the head gasket.that totals 876.877cc now you divide that by 93 cc which is the dish ,chamber, gasket volume 20+64+9= 93 and you get 9.4287 which is a rough comp ratio based on a zero decked block and a .041 thick head gasket with a 4.100 dia bore {fel pro MLS 1142} I did say about 9.5 the ratio will change with a different thickness gasket or changing the chamber volume a few cc's".

Is this a legitimate answer?

bb5401000

iTrader: (2)

That piston has a 20cc DOME. With a zero deck height, .041 head gasket, and 64cc head, it will give you 15.85:1 compression! With flat tops, you'll have 11.8:1. With 15cc DISHED, you'll have 9.9:1. That Wiseco piston with a 76cc head will give you 13.1:1.

Look around on the internet. There's alot of places that have compression calculators.
I have a stock deck height, steel shim head gasket, 15cc dished pistons, 4.030 bore, 3.75 stroke, 64cc heads which gives 10:1.

69Camaro...

iTrader: (8)

how do you figure, this is a 20cc Dish piston Not dome. If your getting 9.9.1 comp. with 15cc DISHED, my compression is obviously going to be lower. I think you got confused

Irocss85

iTrader: (1)

just realize you'll have about .026" deck height. sbc's are almost always right around that area. some pistons could alter that though. so if your doin your math on ZERO deck, just know that your goin to have to deck the block by that much. or however much deck height you end up with your selected pistons.

my setup is -16cc pistons, but I have 56cc chambers in my heads. and a .010 dech height to end up around 10.8:1. your better off goin between 10.0-10.5:1 if you can. try to find a -6cc dish piston, and play around with the head gasket thickness and deck height to get your compress. in that range.

also keep in mind you want about .035-.040" quench for best poss power and knock/detonation protection to allow you to use pump gas.

there's alot of research to do to end up with a great combo unless you just buy a kit from someone who's already done that work. those "packages" almost always use "zero deck" so just make sure to read the fine print, and duplicate it if you go with a kit.

69Camaro...

iTrader: (8)

can i make these pistons work with my application? i have a chance to get them for a really great price with rings

Irocss85

iTrader: (1)

I dont think those will help you reach your goal at all. milling the heads, thin head gasket, zero decking the block will bring your combo closer, but your not saving youself any money by buying the wrong pistons then right? more money in machining costs. and then you gotta worry bout piston to valve clearance and all that if you modify the block deck, and mill the heads and so on.

69Camaro...

iTrader: (8)

that is very true, ill spend the money i save on them on the work to make them work.

69Camaro...

iTrader: (8)

"Ya I agree with that about searching the internet and forums there's a hole lot of people out there that don't know what their talking about . if you need a little more compression you could always mill the heads to 58cc that will get you to 10to1 comp.but then your push 91 octane gas . One thing to remember is you want to keep about .040 piston to head clearance that is the minimum you can have more put you lose comp. Your 210cc head might hurt down low but the extra cubes from the 3.75 stroke should help make it up and help the Hilbourn FI up top.the cam is going to be the must important part of yuor build so get what they recomend don't pick one and say close enough. I've build all my own motors for years from muscle cars to turbo imports to dirt track modifiod and the info you get from a good cam company is well wirth it."

bb5401000

iTrader: (2)

Read the specs at that link, don't look at the picture. The specs say the piston dome is +20cc which means it's a dome. If it said -20cc, then it would be dished. Like others have said, BE CAREFUL-read fine print.

69Camaro...

iTrader: (8)

lol this is right off google.
"Wiseco PT009H3 - Wiseco Pro Tru Forged Piston Kits - summitracing.com
Wiseco PT009H3 - Wiseco Pro Tru Forged Piston Kits - Piston/Ring Kit, Forged, Dish Top, 4.030 in. Bore, 1/16 in./1/16 in./3/16 in. Rings, Chevy, 383, Set of ...
store.summitracing.com/partdetail.asp?part=WIS-PT009H3&view=16383&N=700+115 - 40k - "

And it even says in the summit description that its dished..

bb5401000

iTrader: (2)

O0ps, my mistake. Sorry
You'll end up with 9.45:1 with those pistons.

69Camaro...

iTrader: (8)

no problem

That compression should be fine for my app.