How to lower compression???'s

[dickeymoore]

I just picked up a rebuilt sbc 406 engine and when i removed the heads it has TRW L2311 forged pistons in it that will give me 13.4 compression with my 64cc heads,is there a sbc 400 thicker headgasket with steamholes that I can use to try to get this engine pump gas friendly maybe 11.5 or lower?THANKS

 

[64nailhead]

Not with a headgasket. You could pull the pistons and have them milled and/or make the head chambers a little larger.

Are you planning to race this or just street drive?

What’s the current deck height?

 

[dickeymoore]

daily driver stock deck height

 

[olds307 and 403]

SBC heads are cheap and larger CC should be readily available, go that route.

 

[565bbchevy]

There are a lot of variables for compression ratio, but I think max you will drop will be around 12:1 with even the largest cc performance head.

 

[dickeymoore]

What about a 72cc head and 053. thick headgaskets?

 

[UC645]

What about a 72cc head and 053. thick headgaskets?

If the engine is at 0 deck height, that should put you at 12 to 1 or around there.

 

[olds307 and 403]

It looks like a 75 or 76cc is the biggest available with reasonable sized runners. The 80cc heads have 235 or 245cc intake runners, huge.

 

[565bbchevy]

IMO if you are going to try to make this a pump gas 400 SBC I would replace the pistons with a Hypereutectic or forged piston with lower compression, I think even if your current pistons are a solid dome you still probably won't get below 12:1 with milling and they might also be hollow dome.

 

[dickeymoore]

ok