1970 vs 1971 LS-6

[Stefano]

Used only in the Corvette production for 1971, If memory serves only 188 were produced. I have never had an original appart, and GM specs have varried, but I believe it to be a carry over from the 1970 Chevelle only platform, just with the open chamber aluminum heads.
Same cam and pistons ect...??

[Dutchesscamaro]

Can anyone describe the difference between the 1970 and 1971 LS-6? 450hp vs 425hp
Compression 11.25 vs 9.x?
How was this obtained closed chamber piston with open chamber heads?
Was the cam changed?

Help here would be appreciated...

[Tilbillies]

1970 LS.1 rated @ 450 H.P. had 11.25:1 compression ratio. Mechanical lifter cam, and an 800 CFM Holley, rectangular port cast iron heads, forged pistons and four bolt caps.
1971 LS:6 rated @ 425 H.P. dropped the compression ratio to 9:1.