Flat top pistons v dished

[Redog]

I've been looking around at pistons for my rebuild. I want to have higher CR, maybe around 11:1 (no higher than 11.5:1)

I know that the pistons come out of the block .020, stock HG is .060, which leaves .040 for Compression distance.

With my cam, I'm looking to have a 6500 red line with a 2000-6000 range and quench for that RPM looks to be best at .040.

The DHOC pistons are out, Too much CR for my tastes. With a .080 HG, I'm looking at 12.46:1. They have a dome of .040

Any ideas, from those that know?

[mfuller]

You can do pistons from the 3.4L L32 engine in mid-90's Camaros. Use stock 3400 head gaskets and you're right around 13:1.
You need spot-on tuning to run it on 93 octane pump gas though.
What are the specs on your cam again? High compression needs a fairly large cam to bleed off cylinder pressure at low RPM.
If it were me, I'd still run a dished piston for the safety margin.
This is still a street car.

[Redog]

Cam specs:


259/265 adv duration
210/216 .050" duration
.506"/.506" lift @ 1.6:1 Rocker Ratio
113 Intake Center Line
114 Lobe Seperation AngleAnd yeah, I don't even want to be near 13:1. I think between 10.5 and 11 is best however I'm not sure if it's worth going for higher CR or not

[Papa Rad17]

I'm a little lost here but I think we talking about being able to go faster, if that's the case, I say go all out!!!!
And red, are you running noss? Or was that stuff for air shocks I saw in some pics on an older thread...

[xXManwhoreXx]

11:1 would be fantastic I have,thought about going high comp for a while but I have way to many other projects going on right now.

[mfuller]

Your cam is a bit small for anything over roughly 10.5:1. Above that, cylinder pressures will be very high and detonation is a very real possiblity.
Using 3500 heads will lower your compression about .6 point.......
My new pistons are 11.5:1 on 3400 heads, but since I'm using 3500 heads, it's closer to 10.85:1. And I'll be using a Race cam from Ben.
Figure that that every 1 point in compression on a naturally aspirated 3400 is worth 15HP or so.

[Redog]

I'm going to stick with your old heads. I should be at 9.6 or 9.7 CR right now and I'm still running a stock head gasket. So should I just stick with stock sytle pistions and maybe get a HG of say .055 instead of .060.

So my CR distance instead of roughly .040 it would be .035 and staying in that good quench range

or could I go with a flat top piston and a stock HG thickness.

I'm basicly looking to get the car in the mid 13's. Low 13's high 12's would be awesome, but I'll be very happy with mid/low 13's.

My tranny is slipping a bit, when I replace it, I'm replacing it with a 3.29 FDR tranny. I think the 3.63 FDR is too much

Manwhore: Yes I agree that 11:1 would be awesome, but I want to keep it streetable. That's why I picked that cam, the next one up, may have issues on the street, and Matt knows these engines pretty good so if he's saying I'm going to have problems with higher than 10.5, I'm not going over that

Papa Rad: This isn't the fast and furious. Please don't use the word NOS again, unless you're selling a part that is New Old Stock

[xXManwhoreXx]

Nawwwwwzzzzzz

[Redog]

^^ we already knew your were a ricer :lol:

[xXManwhoreXx]

I was quoting fast and furious

[mfuller]

Can we stay on topic please?

[Redog]

Can we stay on topic please?

That's why I posted in the first post "from those that know" This isn't a post whore thread ;)

\/\/\/ Matt what do youo think about the post quoted below?

I'm going to stick with your old heads. I should be at 9.6 or 9.7 CR right now and I'm still running a stock head gasket. So should I just stick with stock sytle pistions and maybe get a HG of say .055 instead of .060.

So my CR distance instead of roughly .040 it would be .035 and staying in that good quench range

or could I go with a flat top piston and a stock HG thickness.

I'm basicly looking to get the car in the mid 13's. Low 13's high 12's would be awesome, but I'll be very happy with mid/low 13's.