JAH

The LSX LS7 cylinder heads state they need a minimum bore of 4.100. I see the COPO 327 uses LS7 cylinder heads with a 4.065 bore. The intake & exhaust valves are the same size at IN 2.200 / EX 1,610.

What am I missing?

Can I use the LSX LS 7 cylinder heads on a 4.065 bore?

What do I need to watch out for?

Thank you.

lil john

Just get Mast or TFS 255 all others will require work not 2 MENTION CUSTOM WORK 4 the runner their not that good stock or with factory Cnc. Custon Cnc required 2 get your $ worth and the HP that is truely attainable.
Or TSP line of .065 bore high flowing heads...

CAMSTER

iTrader: (10)

Not sure you ready have the heads, in my never to be humble opinion your best option may be heads below, just have them build ready to bolt on with valves and all.

Using ls7 intake manifold correct size intake runners and on shrouded valves very attractive high rpm power and great med range torq using conventional ls7 Fast lsxr intake and 102 mm throttle body

http://www.racingheadservice.com/rhs...r-ls1-ls2html/

lil john

So true they are dirt cheap.. custom Cnc can come later. Factor in 1200.oo for that.

JAH

Thank you for your response.

There are very many choices.

A main one is, to go with LS3 intake manifold, or LS7 intake manifold.

Thank you again.

JAH

Let me see if I have this correct?

LS7 cylinder heads with 2.200" intake and 1.610" exhaust valves will have enough clearance
on a 4.65" bore. Did GM notch the cylinder bores on the COPO 327 block? They will not bolt onto a 4 bolt cylinder head block.

Thank you.

lil john

smaller exhaust valve or a LS7 small bore head.

Jimbo1367

FWIW, I recall in a magazine, they mentioned GM notched/chamfered the top of the cylinder to clear the LS 7valve. I believe something similar like 409s

JAH

Thank you.

I have been looking into the small bore ls7 cylinder heads.

74u

iTrader: (9)

What CC combustion chamber on these RHS Heads?

I have TEA/TFS 225's on my 416 currently...Wonder if there would be enough gain to justify the cost and effort of swapping...

JAH

From Colorado speed site, states the combustion chambers are 66 cc, it is at the top of the page.

CAMSTER

iTrader: (10)

66 cc chambers, ls7 heads using ls7 intake will have the upper hand in my book and certainly my vote....

trevmust

just put a lingenfelter ls9 head on. it will accept ls2, ls3, and ls9 intakes.

JAH

They look like some very nice cylinder heads.

Thank you.

BOLO

iTrader: (40)

Mast LS7 265cc 11* medium bore and their LS7 4500 efi intake is looking good to me.

Black_Phantom

Stock LS7 heads Will clear 4.070" bore, and made 540rwhp on my truck.
The exhaust valve was very close.