Hybrid build

[ForcedFirebird]

I got my 170 casting 3400 heads today (from e-bay for $25+$45 shiping from Cali to FL) and I can't wait to start the new engine! Just from apperance the aluminum heads are far superior. The build is going to consist of 12cc pistons, the 28cc head chambers (1cc of material removed fron the stock 3400 heads), along with .060" compressed height gaskets to yeild a SCR of about 11:1. This in combination of a boosted motor should result in a very interesting result.

I want to thank you guys on all of your pointers thus far and will keep you posted with the progress in this thread.

[discostu]

What is going to be your deck height for the pistons?
By my calculations you need to be .010" down in the bore to achieve 11:1, but that will give you a quench distance of .070" essentially killing your quench.
Your detonation resistance will be reduced by a large margin... You should have a bigger dish and a quench distance of .040" for the best results of power and detonation resistance.
Perhaps you should machine your pistons for a 16cc dish and have them out the top of the block by .020" inches...
That would give you the same 11:1 compression, but you would have FAR superior detonation resistance.

[ForcedFirebird]

I could use the stock size gasket and it would give me 11.92:1 which is the way I might go.
With the aluminum heads what kind of SCR could I get away with on pump gas (93 octane).

By my calculations you need to be .010" down in the bore to achieve 11:1

.0165 is the stock deck height

Perhaps you should machine your pistons for a 16cc dish and have them out the top of the block by .020" inches...

I already purchased the pistons, they're Keith Black .030" over hypers.

EDIT: I used the CR calculator here on the site:

You have selected to use the following values for your compression ratio calculations:

Bore 3.534"
Stroke 3.307"
Head Gasket Bore 3.69"
Head Gasket Compressed Thickness .040"
Combustion Chamber Volume 27 cc
Piston Dome Volume 12 cc
Piston Deck Clearance .0165"
Displacement 3188 cc
Calculated Compression Ratio 11.92:1