aluminum valve cover bolt dimensions

[35chevcoupe]

I,m getting close to wrapping up my engine rebuild but don,t have any valve cover bolts for the aluminum buick covers .
Does anyone know the correct size and length ?  Ordered the wire looms from Russ martin but now need the bolts . Also were the bolts chrome or painted ?
Thanks in advance

[cwmcobra]

Hi John,

Here's what came on my car.  i think it's correct, but maybe Loren or others can confirm.  Heavy chrome plated flanged head bolt with 1/2" hex and 5/8" diameter flange.  Raised "NL" in center of head (like the way the word "centerline" is usually abbreviated - L in the middle of the N).  5/16" diameter x 18 pitch thread, ~3 3/8" long.  Pictures attached. 

AMK has a bolt about the right size and characteristics, but no chrome plating.  B-12711 on page 25 of their catalog.

There are rubber grommets that seal the underside of the flange on the bolt to the valve cover.  Carmen has them; I suggest you buy a set from him to include with your carbs.

Cheers!

Chuck

[TrunkMonkey]

I put a grade 8 flat washer under the head of the bolt and on top of the rubber gasket to keep it flat. (Painted green to match the covers)

Even if it is not over-torqued, the rubber gasket still "dishes" and I want it flat, dagnabit. 

[35chevcoupe]

Thank guys  for the info. Chuck I see there is another bracket or clip holding a vacum line , is that part of the plug wire loom bracket or is that a separate piece ?

[Mark Ascher]

John,

It?s a separate piece. For the PB booster vac line. If you don?t have that line, I may have an extra. I know where you can get one if I don?t.

Mark

[cwmcobra]

It's a separate piece that came on my car.  I'm not sure it's correct.  It seems to fit nicely, but I'll confirm that when I install the carbs (the ones on there now are mockups).  Loren sent me a couple of pictures of the correct clip.  It might be that I need to bend an angle into mine and it will work.  Loren's pictures are attached.  The correct clip for the Super Wildcat setup is the chrome plated one.

Chuck

[cwmcobra]

John,

It?s a separate piece. For the PB booster vac line. If you don?t have that line, I may have an extra. I know where you can get one if I don?t.

Mark

Yep, I bought my vacuum line from Carmen.

Mark, do you know of any sources for the correct chrome plated vacuum line clip for the Super Wildcat?

Chuck

[35chevcoupe]

Mark , Chuck ,   I do not have the vacuum line tube yet but I believe Carmen is making one up for me along with the fuel lines  .
I have two sets of valve covers but i see there is a minor difference in them . The difference is where the rear hold down bolt goes through , 1 set the recessed area is round and the other set the recessed area is square .    I need to find that vacuum line bracket as I do not have one of those .

[WkillGS]

A composite rubber washer from the hardware store or plumbing supply also works well to seal the bolt to the valve cover.  Also used on the valley cover bolts. The Fel Pro gasket sets include the washers.
I think the valley cover bolts are similar to the valve cover bolts, but not pointed at the end?

[Brian]

My experience has been that the bolts that came on the green stock valve covers are the same except for needing chrome plating.

[35chevcoupe]

My experience has been that the bolts that came on the green stock valve covers are the same except for needing chrome plating.

Brian , I just pulled one from a spare complete engine that I have here that has never been taken apart and you are correct .
Even has the correct markings on the bolt head .
Thanks for the input guys . guess i,m making another run to the chrome shop .

Walt , actually I double checked the length and the valley pan bolts are even a better match , they are 3/16 shorter than the valve cover bolts .
They fit perfect .