Hey guys,

When I built my stroker I was fully intending on getting a new set of heads to lower the compression ratio when it came time to put on the boost. However, now that it's come time to do this my pocket book can't handle the extra $3k for a set of AFR's and a new intake with the cost of everything else I'm doing this winter.

I was thinking of grinding the Stock combustion chambers on my ported heads to open them up and then get a .074 thick Cometic head gasket. This should get me to where I want to be. Do you guys have any opinions on doing this? I know it's only a bandaid until I can affrod the new heads.

Is there a better way of lowering the compression ratio?


Thanks for the help,

 

TTT, anybody have any opinions or comments???

 

mn vette,

what is your current setup/ pistons, deck height, etc and how much compression do you currently have? First off a .074 gasket will KILL good combustion and flame travel. Also unless you cc each combustion chamber it will be risky to open up the chambers and keep them consistanly sized. This can also hurt your performance if you get too far away from the original chamber design. If your compresion ratio is not too extreme right now you might be alright taking some timing out to reduce cylinder pressure. What camshaft do you have? A bigger camshaft will bleed off low end cylinder pressure and help keep detonation awayon the street but you might still end up needing race gas to go all out at the track. This is not a perfect solution but it may let you enjoy your ride till you can save up for those heads and build the engine like you planned. Hope this helps.
The captain

 

I'm in the same boat with a too high of a CR, so I'll be swapping out pistons for to a set that's coated and dished somewhere around 36cc. That will put me around 8.6:1.

Like above, what are all the specs for the motor now?

 

Current set up is this:

4.03 diameter
3.85" stroke
-24cc pistons
zero decked


I'm at around 9.9:1 with 58cc chambers. The cam is going to be some form of turbo cam I'm not sure what I'm going with, hopefully in the range of 220-230 duration on each side.

I'm planning on running 10psi to start out with. I'd like to do it without too much timing retard, but it that is what it takes to keep the engine going so be it. I'm looking for the most performance without destroying something. I'm still hoping that this setup will get me into the 10's

 

Shoot me an e-mail: Scott@Lateral-g.net I have a very good friend building a twin turbo 383 LT1.

 

Cats out of the bag Scott who is it? Is it going into a 4th gen? Perhaps a white one?

 

you can have pistons machined if they are thick enough but i dont suggest it.
I also dont like thicker head gaskets for lowering compression. mill the heads/intake and maybe deck block?
you should be able to "weasel" down to 9.5

our car at work runs 11:1 boosted

 

10 psi with pump gas should be fine with that compression, just keep the air temp down. Then when you can get the heads turn the boost up.

 

So you think with the 9.9:1 CR I should be able to run 10# just fine without worries? Then turn up the boost when I get new heads. hmmmm, perhaps, but I'd like to error on the side of caution. Maybe 9:1 is a little too much to shoot for.