Boosted LS1

I'm curious about these heads and wondering if anybody has machined the combustion chambers out to ls7 dimensions/volumes. Is there enough material to enlarge the chambers? I've done a search but can't find anything relevant or even if they're viable. I know the port locations are different on the intake. Thanks.

ls1290

iTrader: (20)

The C5R head chambers are 'naturally' 38cc. The most I have heard them being opened up to is 44cc. The heads require a 4.125 bore cylinder. Some of the biggest dish pistons I have heard are about -34cc. With a stock length crankshaft, that will ive you a compression level of 9.4:1 and a 388 CID displacement. You could definitely run a good amoutn of boost on that motor. Using a 3.75" crank, that will give you 10.1:1 and a 401 CID displacement. Still somewhat boostable. Goign with a 3.9" or 4.0", your compression level is get over 10.5:1 to 10.7:1. You can still run a S/C, but the compression level restrict the amount of boost you can run.

Keith

Boosted LS1

Thanks Keith, the c/r is what's restricting the boost on a 427 build I'm planning hence my wondering how big the chambers can be machined out. If I could get to 70cc like ls7 these heads could be of use to me. Either that or downstroke as you've mentioned.

ls1290

iTrader: (20)

There is no possibility that the chambers can be opened to 70cc. You have to use a big dish piston to drop the compression level. With a 427 CID, 4.00" crank, the best CR you can get is 10.7:1.

Keith

Boosted LS1

Thanks Keith. So I take it nobody's looked to see how much metal is in the chamber walls? I drilled out an ls7 head and lets say there wasn't any excess material. I'm pretty sure my last build with ls7 heads got me down to a measured 9:1 with custom bowled pistons. I'd just like to go a bit lower for the next build.

HUNTER02SS

iTrader: (24)

Boosted LS1, I sent you a pm for some people that built a 400ci. C5r race case with C5R head's and twin Turbonetics76mm turbo's. Not sure on the compression,but they can help with your questions!

Boosted LS1

Thanks Hunter, I'll call them later. I've sent you a reply.