63 L84 exhaust manifod studs

[Rob M.]

In my driver side (corrected) exhaust manifold the studs are too long and the thread is not running far enough to be able to tighten the nuts (there is no 1"thick spacer needed for '63 L84)

On my passenger side (corrected) exhaust manifold they are too short, here a spacer is needed (with the heat valve) so also here I need different studs.

How do I get rid of these studs, I understood they are probably hardened by the exhaust being hot and cold, hot and cold, etc... any advice on what to do???

Where can I order these studs? I could find them in the CC online shop...

[Michael G.]

Re: 63 L84 exhaust manifod studs

Rob, I'm not sure which side you're referring to as you state "right" for both manifolds.

In any case, the right hand (passenger) manifold on a 63 L84 uses a 1" spacer to replace the heat riser valve. The driver side does not. I've had success getting them out with penetrating fluid, but mine weren't rusted that bad.

Most Corvette vendors stock stainless versions of the studs. I bought some correct carbon steel parts a couple of years ago, but haven't seen any for sale lately.

[Gary F.]

Re: 63 L84 exhaust manifod studs

Nice pic of spacer at Corvette Central....Item 322113 for 2.5 inch exhaust, L-84. It is for the passenger side exhaust manifold. Studs are available. If penetrating oil doesn't do it, I lightly heat the surrounding area of the stud to expand it, then use vise grips to crank it out. To each his own.

[John H.]

Re: 63 L84 exhaust manifod studs

In my right exhaust manifold the studs are too long and the thread is not running far enough to be able to tighten the nuts (there is no 1"thick spacer needed for '63 L84)

On my right exhaust manifold they are too short, here a spacer is needed (with the heat valve) so also here I need different studs.

Rob -

Your passenger side studs are longer, to accommodate the thickness of the spacer used on L84 engines in place of the heat riser valve used on all the other engines. Your driver's side studs are shorter, as there is no heat riser valve or spacer used on that side.

[Joe L.]

Re: 63 L84 exhaust manifod studs

In my driver side (corrected) exhaust manifold the studs are too long and the thread is not running far enough to be able to tighten the nuts (there is no 1"thick spacer needed for '63 L84)

On my passenger side (corrected) exhaust manifold they are too short, here a spacer is needed (with the heat valve) so also here I need different studs.

How do I get rid of these studs, I understood they are probably hardened by the exhaust being hot and cold, hot and cold, etc... any advice on what to do???

Where can I order these studs? I could find them in the CC online shop...

Rob-----

The original studs were GM #3760425, left side, and GM #3760426, right side. They're long-since GM-discontinued but exact duplicates are available from AMK Products.

Another option is the current GM SERVICE studs. The shorter left side are GM #14088827 and the longer right side are GM #14088828.

Would I use either of the above? Absolutely, positively NO. I would use only 304 or 316 stainless steel studs.

[Dan B.]

Re: 63 L84 exhaust manifod studs

As far as removing them, if they are really stuck in there, your best bet would be to heat the manifold with a torch to get them out. If you attempt this cold they will likely break off and need to be drilled out. Any good muffler shop could do this for you. Dan