LT-1 head casting #'s

[tonyk72]

Why is it that there were different heads placed on the (72) LT-1?
I looked up what I have... 3998993, I can see the # when I remove the oil filler cap. From the research I've done, the valve sizes on these are 1.72/1.50 or 1.94/1.50...which would they be? Also, I see that other castings were used like 3973487 which used 1.94/1.50 & 2.02/1.6 & 3998916 which used 1.94/1.50..i think?

 

[tonyk72]

Where is JohnZ? Haven't seen him post in a while...
Good info so far though...would going to any of these other heads (with bigger valves) be basically a bolt on job? I wanna go faster and stay as stock as possibe!

 

[72LT1Steve]

Well based on the general question of the post and the responses. I went down and checked my head casting number for a little comparing. I know the previous owner had gone through the engine & generally upgraded the internal parts. I found my head number to be 3927186. I knew that wasn't any of the head numbers that have been discussed. So I checked the handy dandy Vette Black Book and noted that they were used for the 1970 LT-1 motor. I going to assume that might be a good thing (for performance anyway)

 

[tonyk72]

I was going to pick up a set of the 487 heads on ebay, but found that one of them was actually a 487X. Not sure if the owner knew about the differences...
Also, from the additional research I've done, some claim (various forums) that the 487X heads were the 1.94/1.50 valves...& not the larger sizes...