1972 LT1 - rocker stud

[Jerome P.]

I have gotten conflicting answers from local friends. The question is three part:

• Do all 70 - 72 LT1's have screw-in rocker studs or were the screw-in studs eliminated in favor of the press-in studs sometime during the the 72 model year?
• What Cyclinder Head did the 1972 LT1 have on the engine for late 72 models? was it part #3973487, #3973487X?
• What is the difference between the 487 and the 487X Heads?

Thanks in advance for your thoughts and comments.

Jerry

[Joe L.]

Re: 1972 LT1 - rocker stud

I have gotten conflicting answers from local friends. The question is three part:

• Do all 70 - 72 LT1's have screw-in rocker studs or were the screw-in studs eliminated in favor of the press-in studs sometime during the the 72 model year?
• What Cyclinder Head did the 1972 LT1 have on the engine for late 72 models? was it part #3973487, #3973487X?
• What is the difference between the 487 and the 487X Heads?

Thanks in advance for your thoughts and comments.

Jerry

Jerry------

1) All 1972 LT-1's used screw-in studs, regardless of which cylinder head was installed. As a matter of fact, the follow-on L-82 all had them, too;

2) I think that late 1972 LT-1 could have used either the 3973487X or 3986316 cylinder heads;

3) I don't know of any difference between the '487' and '487X' heads (except for the "X"-suffix, of course)

[Jerome P.]

Re: 1972 LT1 - rocker stud

Thanks Joe. As in the past you continue to be very helpful and responsive. I am getting feed back that the 487X's are the heads used for the late 72 model year LT1's and they did not have the screw-in studs. Any validity in, your mind, to this thought?

Is there any manuals/publications that would help support yours and my thoughts on this topic?

Again thanks. Look forward to hearing from you.

Jerry

[Joe L.]

Re: 1972 LT1 - rocker stud

Thanks Joe. As in the past you continue to be very helpful and responsive. I am getting feed back that the 487X's are the heads used for the late 72 model year LT1's and they did not have the screw-in studs. Any validity in, your mind, to this thought?

Is there any manuals/publications that would help support yours and my thoughts on this topic?

Again thanks. Look forward to hearing from you.

Jerry

Jerry-----


As with many small block cylinder heads, the GM #3973487X was manufactured with both pressed-in and screw-in studs. The versions with the pressed-in studs have 1.94"/1.50" valve size. Versions with 2.02"/1.60" valve size have screw-in studs. All LT-1 used the 2.02"/1.60" valve size.

When someone shows me a set of ORIGINAL, UNMODIFIED, PRODUCTION (i.e. NOT SERVICE) 3973487X heads with the 2.02"/1.60" valve size and pressed-in studs, I might believe that such heads were once produced. I don't think I'll ever see any, though.