Head casting numbers
Thread Starter
Burning Brakes
Joined: Dec 2002
Posts: 1,069
Likes: 2
From: Sherwood Park AB
Head casting numbers
My heads casting numbers are as follows:
3986336 K20 A/07
I was told these are 76 cc from a 71 350. How do these compare to the L82 heads? What is the compression ratio?
:cheers:
3986336 K20 A/07
I was told these are 76 cc from a 71 350. How do these compare to the L82 heads? What is the compression ratio?
:cheers:
Drifting
Joined: Nov 2000
Posts: 1,428
Likes: 0
Re: Head casting numbers (rexx78)
After researching my Corvette Black Book ( Something no C-3er should be without), I can assure you that the 336 Head was never original equipment on any C-3..........No other facts and figures avail because of that. GOOD LUCK!
Drifting
Joined: Dec 2002
Posts: 1,861
Likes: 2
From: New Zealand
Re: Head casting numbers (rexx78)
I haven't been able to find any further info on your heads 3986336 K20 A/07, except that K20 should be the date code and could read NOV 2 1970. BTW, the "0" in the date code is the year digit, and could mean 1960, 1970 or 1980....but late 1970 is closer to the only listing http://home.isoa.net/~mharrisj/sbcheads.html I have found for your head casting number.....BTW, I don't know what A/07 stands for....
The 1978 L-82 specs are as follows (according to http://www.vettefinders.com/78registry/1978spec.html):
chamber volume 76.18 cc
compression 8.9:1
Intake Valve 2.017 - 2.023 in
Exhaust Valve 1.595 - 1.605 in
Head Casting number 462624
To compare your existing heads to an L-82 you will have to (as a minimum) check the compression, measure your existing INTAKE/EXHAUST valves, and find out your existing cam specs.......basing your decision on a casting number may not be reliable because your existing heads may already have been modified.....
I hope this helps......
The 1978 L-82 specs are as follows (according to http://www.vettefinders.com/78registry/1978spec.html):
chamber volume 76.18 cc
compression 8.9:1
Intake Valve 2.017 - 2.023 in
Exhaust Valve 1.595 - 1.605 in
Head Casting number 462624
To compare your existing heads to an L-82 you will have to (as a minimum) check the compression, measure your existing INTAKE/EXHAUST valves, and find out your existing cam specs.......basing your decision on a casting number may not be reliable because your existing heads may already have been modified.....
I hope this helps......
