1970 LT1 Valve Covers

[James H.]

I have a 1970 LT1 that i am working on to be reasonably correct, and a good driver car. I have one of the valve covers that is cracked, at one of the bolt holes. Has anyone had any experience with sending these off for repair, where the repair would not be noticeable unless you knew it was there?

Plan B would be to buy A NOS set (so they would match), or I would be OK with a really good reproduction set.

I saw a GM Restoration set from paragon that looked the best, but I am open to any advice.

Thanks

Jim

[Ron G.]

[John S.]

[Joe L.]

Re: 1970 LT1 Valve Covers

Jim, no personal experience with aluminum repair but I would think if you “v” out the crack, an experienced aluminum welder should be able to fill it back in pretty decently. You may have to polish up your Dremel skills to properly finish off the flatness and appearance.

One note on the reproduction covers and I could be wrong, but most I have seen are correct for later L82 cars such as mine with the twist in oil filler cap. I believe your LT1 has the rubber plug push-in type that requires a simple round hole, not the notched hole found on the later twist in covers.

A few years back I helped a guy on another forum locate a pair for his LT1 and that’s how we found out the difference. Good luck and compare the repros to your originals before you buy.

John------

I agree on the repair.

All 1970 engines used twist-lock oil filler caps. 1971-E1972 small blocks used the push-in rubber plugs for both steel and aluminum valve covers. 1971-74 big block valve covers used the rubber plugs.

[James H.]

Re: 1970 LT1 Valve Covers

Any ideas for a source of NOS valve covers would be appreciated. I have looked a bit on line and I am not coming up with any options.

Thanks for the feedback.

Jim

[John S.]

Re: 1970 LT1 Valve Covers

Joe, thanks for the clarification, the guy I was helping did have a 72 LT1. Interesting that GM started with the twist lock aluminum covers, switched to the push in, then back to the twist lock.

[Joe L.]

Re: 1970 LT1 Valve Covers

Joe, thanks for the clarification, the guy I was helping did have a 72 LT1. Interesting that GM started with the twist lock aluminum covers, switched to the push in, then back to the twist lock.

John-------

I think the switch back was the result of the resounding failure of the rubber plugs. They were MISERABLE. They rather quickly became hard and brittle and became difficult to remove and install. Even when the plugs were brand new they were a bit of a pain to remove and install.

[Joe L.]

Re: 1970 LT1 Valve Covers

Any ideas for a source of NOS valve covers would be appreciated. I have looked a bit on line and I am not coming up with any options.

Thanks for the feedback.

Jim

Jim------


For absolutely authentic valve covers you'll need to find a GM #3965541 and 3965542. Finding those in NOS condition will be a tough nut to crack. Each of those was discontinued in 1980. 40 years is a long time for any existing supply to dry up. However, the 3965541 was replaced by GM #474207 and 3965542 was replaced by GM #474208. As far as I have been able to determine, the replacements differ only in the degree of polish and cast-in part numbers. The part numbers are on the bottom, unseen when installed and, thus, irrelevant.

The 474207 and 474208 remain available from GM.

What's really hard to find is the 1971-E1972 left side valve cover with plug type oil filler, GM #3990994. Mercifully, it lived a very short life being discontinued in August, 1973. Of course, the only folks that would want one would be folks trying to do an authentic restoration of a 1971-E1972 LT-1.