1972 LT-1 valve cover bolt head markings

[Michael B.]

On my LT-1 valve cover bolts I have six with an "R" head marking, and two that are obvious replacement hardware store bolts. I have only seen "M" head markings offered as replacements in recent catalogs. Does anyone know what is correct for a June 72 LT-1? If the "R" is correct, any advice where to source them? Thanks.

[Roy V.]

Re: 1972 LT-1 valve cover bolt head markings

If you still have your last issue of "The NCRS Driveline" handy, go to page 36 and 37, there you will find an ad for
Richard Fortier Corvettes,LLC, he's also known as the fastener king (it says so right in the ad).
I would imagine he would have what you need
Regards
Roy

[Ron G.]

Re: 1972 LT-1 valve cover bolt head markings

Michael - Thats right. Usually "M" is the one that is most often seen. However, that does not mean that there isn't others. The most important thing is the configuration the bolt which is a indented hex head. If my memory is correct, yes "R" is one that I have seen on some 72's and thereofore would be acceptable.

[Michael B.]

Re: 1972 LT-1 valve cover bolt head markings

Thanks again. I'll give Richard a call tomorrow.

[Michael B.]

Re: 1972 LT-1 valve cover bolt head markings

I'm also assuming all eight bolts would need the same marking, right?

[Roy V.]

Re: 1972 LT-1 valve cover bolt head markings

Michael, I'm not at home until tommorow am, I will check mine and let you know what I find.
Regards
Roy

Edit I have a couple of pictures that I can access from my photobucket account, but there not clear enough to really determine what letter is on the head, I will let you know tommorow

[Ron G.]

Re: 1972 LT-1 valve cover bolt head markings

In 72 the bolts in queston do not necessarlily have to have all the same head marks. We have seen 72 LT-1's with "M" and "R" bolts on the same engine. These are Bowtie and Survivor Corvettes. Just like any other component on the car, as long as the hardware is to spec, the bolt logo does not matter. There was and still is what I like to refer to is the GM Family of hardware, because there were several vendors that supplied hareware to GM.

[Russ S.]

Re: 1972 LT-1 valve cover bolt head markings

Both of my 73 L82s which use the same valve cover have all Rs.

[Joe L.]

Re: 1972 LT-1 valve cover bolt head markings

In 72 the bolts in queston do not necessarlily have to have all the same head marks. We have seen 72 LT-1's with "M" and "R" bolts on the same engine. These are Bowtie and Survivor Corvettes. Just like any other component on the car, as long as the hardware is to spec, the bolt logo does not matter. There was and still is what I like to refer to is the GM Family of hardware, because there were several vendors that supplied hareware to GM.

Ron-------


Yup! The only way to know what headmarking bolts were on a particular engine is to have the bolts originally installed on that engine. In the case of this application for which there were at least two known headmarkings (and, maybe more), there's absolutely no way to tell which were originally used on a particular engine.

By the way, an "M" headmarking, for Michigan Screw and Bolt, is a VERY common, period-correct headmarking for many bolts used on Corvettes. Michigan Screw and Bolt was a major supplier to GM at the time.

[Ron G.]

Re: 1972 LT-1 valve cover bolt head markings

Joe - Yes I know that "M" is for Michigan Screw and that they were very common on Corvettes. Also, the were used all over the rest of the car. I was replying to Mick B. in response if all the head markings were the same on Roy V's car and I made mention that basded on what I have seen for 72 LT-1's, there is evidence of both the "M" and "R" used on the same engine. Also, I have a sheet that me and my judging colleages assembled many years ago that I refer to as the GM family of hardare that I would be happy to share. My experience is based on known Bowtie and Survivor cars.

[Michael B.]

Re: 1972 LT-1 valve cover bolt head markings

Ron, I'd sure appreciate a copy of that hardware sheet. I've got lots of incorrect bolts and I'd like to ensure I'm replacing them with the right ones. If you can email the sheet that would be great; [email]mikebrezden@gmail.com. Thanks

[Roy V.]

Re: 1972 LT-1 valve cover bolt head markings

Michael, I removed one of the 8 bolts that attach the valve cover to the head, they all have the "R" stamp in them.
the one I removed is a 1/4 x 20 thread by 1 inch in length, I don't know if any of the others are longer, I didn't remove them.





Regards
Roy

[Michael B.]

Re: 1972 LT-1 valve cover bolt head markings

Thanks for checking that for me. Like I said beginning this thread, two of mine are missing but the remaining six are all "R". I checked another 72 LT-1, serial #18205, and all eight were "R". Now at least I know that's correct and what I need to look for.