99 Black Bird T/A

iTrader: (4)

FWIW:

Saw this on ebay today. TEA's Ebay Store, some LS1 engine stuff including heads and several cams.

http://www.stores.ebay.com/id=957605...;ssPageName=L2

VINCE

iTrader: (1)

They have some 55cc heads.. Wow!!! What the hell compression is that? How much do you have to mill off a 5.7L to get 55cc????? I do not think my 2cc valve reliefs would be enough for those heads..

99 Black Bird T/A

iTrader: (4)

Vince, maybe 12.2 to 12.3, beats me but it's high!

Tin Indian aka Ron posted this

https://ls1tech.com/threads/showflat...rue#Post671287

Known:

A 5.7L LS1 head has a chamber volume of exactly 66.67cc and 10.1 CR

A 5.7L LS6 head has a chamber volume of exactly 64.45cc and 10.5 CR

That means a decrease of chamber volume of 0.56cc = an increase of 0.1 CR

66.67cc = 10.1 CR (stock LS1 spec)
66.11cc = 10.2 CR
65.55cc = 10.3 CR
64.99cc = 10.4 CR
64.43cc = 10.5 CR (very very close to the actual 64.45cc LS6 spec)
63.87cc = 10.6 CR
63.31cc = 10.7 CR
62.75cc = 10.8 CR
62.19cc = 10.9 CR
61.63cc = 11.0 CR
61.07cc = 11.1 CR
60.51cc = 11.2 CR
59.95cc = 11.3 CR

Now, these numbers are based on a linear set of numbers. I can't be sure, but I would think that a change in head chamber CCs vs it's corresponding CR would be linear.

VINCE

iTrader: (1)

Thats close enough for me. I am sure my cam would bleed off the compression, but I do not know if my p/v clearance would be ok.. I do have valve reliefs, but wow..

Tin Indian

Here are some more specs:

72.27cc = 9.1 CR
71.71cc = 9.2 CR
71.05cc = 9.3 CR
70.59cc = 9.4 CR
70.03cc = 9.5 CR
69.74cc = 9.6 CR
68.91cc = 9.7 CR
68.35cc = 9.8 CR
67.79cc = 9.9 CR
67.23cc = 10.0 CR
66.67cc = 10.1 CR (stock LS1 head spec)
66.11cc = 10.2 CR
65.55cc = 10.3 CR
64.99cc = 10.4 CR
64.43cc = 10.5 CR (stock LS6 head spec)
63.87cc = 10.6 CR
63.31cc = 10.7 CR
62.75cc = 10.8 CR
62.19cc = 10.9 CR
61.63cc = 11.0 CR
61.07cc = 11.1 CR
60.51cc = 11.2 CR
59.95cc = 11.3 CR
59.39cc = 11.4 CR
58.83cc = 11.5 CR
58.27cc = 11.6 CR

VINCE

iTrader: (1)

So I need 73cc heads for my next setup..

Phil99vette

iTrader: (11)

LOL I've got a set of 56cc heads on my car with a THIN Headgasket.
Phillip

VINCE

iTrader: (1)

Wow!!! You have a big cam as well right?

99taws6

iTrader: (2)

55cc on the sheet I am looking at is 11.87

VINCE

iTrader: (1)

Now that is some compression?

Phil99vette

iTrader: (11)

If I remember correctly 12.3:1 with my shortblock.