3400 Heads on a Flat Top Piston Iron Head 3.1

[eph_kay]

Ok, I was messing with the CR calc and have some questions.

First off I have a nonroller cam 3.1l block that I got a few years ago that has flat top "10:1" pistons, and I think a 260 or 252 cam, not quite sure, and then has ported fiero heads and valvetrain. Well I don't want to run the iron heads on this motor, and I have spare 3400 heads laying around, and all I remember is people saying that taking material out of the combustion chambers was the only way to get the comp down to an acceptable level.

Anyway I plugged some numbers into the CR calc, the motor is a 3.1 crank and rods with .060 over flat top pistons, and then I put in 28.6cc for combustion chamber volume. Then I went and put in the biggest head gaskets WOT-Tech offers, the .089 MLS gaskets and came up with a 12.53 comp.

Do any of you feel this could be run with 91 octane gas? e85? where I live there isn't any 93 and I don't know where there is e85 and would prefer to not run it. Could I get away with running the higher octane with a really good tune? A local guy has a chip burner, and if I could set it up on OBD2 I have HP tuners.

Thanks,
Chris

[SappySE107]

You need a much bigger cam to run that kind of compression.

[geoffinbc]

Agreed. Don't have ass a build in attempt to save a minor amount of money on a set of stock replacement pistons.

[eph_kay]

I hear ya, and I wasn't really attempting to save money I guess, I have two sets of ported iron heads, and 2 sets of 3400 top ends, and the 3.1 shortblock is already assembled so it was more the attempt to use up what I had without having to buy another shortblock. I can build it with the iron heads, but they just make me sad, but it wouldn't stay any my car, it would just get built swapped running and sold.

Iron heads it is.

Chris

[Pretty Boy]

Chris its (Justin) and man i really wish you don't get rid of that block though about setting some cash back and trying to get it from you and run that till i blow it up than build me a 3.4 outta it with my 3.4 parts lol as a playtoy motor build till i get up all the parts for my 34/3500 hybrid swap!