396 Valve Cover Bolts

[John O.]

Ok 396 ****hes, here is another bolt question concerning the valve covers. My original bolts are "TR" bolts and non-recessed hex heads. This conflicts with the JM which states they are recessed and typically RBW. Do any of you have info on this? It doesn't sound like you can get a deduct from the use of the word "typically". From information gathered from many of you over the past month concerning 396 engine fastners it sounds like the 65 JM needs a little update. I really don't want to change these over as they are original but I don't want the "hit" either.

Many thanks,
John Osterholm

[Chris H.]

Re: 396 Valve Cover Bolts

John, regardless of what the JG says, if you know your fasteners are original, leave them as is. The JG can be updated with your new information.

We all know that JGs have "errors" and get updated over time as new information becomes available.

[Gene M.]

Re: 396 Valve Cover Bolts

Your TR bolts are correct. That's one of about three supplies that GM used to fill that application. There may be even more depending on the time the parts order was made.

[Michael H.]

Re: 396 Valve Cover Bolts

John,

What size is the hex on the bolt? If you have flat TR's, that sounds more like the bolt they used starting in mid 66 for the 427.

Michael

[John O.]

Re: 396 Valve Cover Bolts

Michael:

Mine are the flat with raised "TR", my car is very late 22161 mid July build....think I would get a deduct on these?

Thanks,
John

[Michael H.]

Re: 396 Valve Cover Bolts

John,

If the bolts that you have are 7/16" hex flat head, I would have to guess they would get a deduction but I'm not exactly sure how the Judging Guide reads on these. The originals, at least what I've seen over the years, were a unique 3/8" dished hex head instead of the 7/16" that came in some time in the middle of 66 production.

Michael

[Joe L.]

Re: 396 Valve Cover Bolts

Michael---

That surprises me. I've never seen a 1/4" bolt of the period, either trimmed ("flat" head) or untrimmed ("indented" head), that used a 3/8" across-the-flats dimension. The standard head dimension for 1/4" bolts was 7/16" across-the-flats. In today's world with reduced head size fastners being used in PRODUCTION and widely available in the aftermarket, such a thread/head size combination is quite common. I never recall seeing it in the 60s, though.

[Michael H.]

Re: 396 Valve Cover Bolts

Joe,

In the mid 70's, I found and purchased the now famous 65 396 conv that David Burroughs wound up restoring (Corvette Restoration, State of the Art) and altho it had a lot of miles on it, the original 3/8" dished head screws were still in place. There were a lot of reasonably complete all there cars available to view then and every one that didn't have M/T valve covers, had the 3/8" hex.

Another good example is the also quite famous and well known 65 396 conv that has somewhere around 3000 original miles on it. That car was absolutely untouched when I first saw it and it too had the 3/8" bolts.

I can think of no logical reason why GM, or Tonawanda, decided to use these but I know they did and if I remember correctly, they were replaced with the more common flat head 7/16" TR, RBW, A etc bolt in mid 66 production.

We need to hear from some of the 396 guys out there on this.

Michael

[Joe L.]

Re: 396 Valve Cover Bolts

Michael------

As I say, it surprises me but I didn't mean to imply that I think it didn't happen. It would be, though, the only use of "reduced wrenching size" bolts on cars of this era that I am aware of.

[Michael H.]

Re: 396 Valve Cover Bolts

Joe,

I've never been able to figure out their reasoning on this either. I see no purpose for the smaller head, other than possibly the heads were a bit taller and held in the driver better in production. Whatever it was, it was gone by mid 66 so we'll probably never know for sure.

Michael

[Daniel W.]

Re: 396 Valve Cover Bolts

Hello all,

Our 40000 mile 396 car has 1/4" bolts that require a 3/8" wrench on all valve cover bolts with the exception of the bolt retaining the steel tubing that connects to the right hand exhaust manifold. It takes a 7/16" wrench and is not painted engine orange. Also, an early 1966 427/450 car within viewing distance has all 1/4" bolts requiring a 3/8" wrench.

Dan

[Bill W.]

Re: 396 Valve Cover Bolts

John the bolts out of 16120 are recessed RBW without the circles shown in the Paragon book.3/8ths head size.If you think the TRs or original I would stick with them.Bill