CA-Legal-Vette

After struggling far longer than I care to admit to put the passenger side exhaust back together with a new insert and donut, I discovered that it went together perfectly without the heat riser spacer.

Do do people with side pipes include a heat riser or spacer?

Are the studs supposed to be longer on the heat riser side than on the drivers side? I just couldn’t get the nut to start. I really thought that once the donut compressed a little, it would be fine.

7T1vette

I would think that GM put heat riser gizmo on all engines (except maybe the L-88/L-89's). But, unless you intend to drive it around in the winter, you don't really NEED the heat riser.

CA-Legal-Vette

I definately don’t have a heat riser. Prior to adding the sleeve and donut, the studs were long enough even with the heat riser spacer in place.

TimAT

I agree with 7T1-- where you live, you don't need a heat riser. And yes, the studs were longer on the right side to fit the added length of the heat riser (or spacer). And you have figured out the sleeve donut thing along with the flat gasket between the top of the spacer and the manifold..

CA-Legal-Vette

Alright then. I’ll leave it as is.

Thanks to both of you.

0Willcox Corvette

You don't really need a heat riser, but keep in mind that side exhaust pipes are made to acclimate to either a heat riser or a spacer one or the other.... If nothing is used then the pipe won't fit properly to the exhaust manifold. Yes the studs are longer but you have to factor in that the pipes are made, whether your are using mid year or 69 style pipes, for having this space in the system.

If you don't run the spacer or a heat riser valve you pipe's will not seal properly to the manifold. IMHO...

I'ts been a long day, hope I'm not being confusing...

E

CA-Legal-Vette

I appreciate your input Ernie. Do you have a part number for the longer studs?

0Willcox Corvette

You've been a great customer over the years, but in this case... I'm cutting my wrist...lol..

You can probably buy them from your local parts house... it'd be cheaper...

Dorman 03147 is the part number... comes with three long and three short studs the nuts...

You should be able to bet this at your local parts store... I'll catch you on something else later...

Ernie

7T1vette

They don't make 'em like Ernie, any more.....

CA-Legal-Vette

Again, I appreciate it. I’ll probably wreck the manifold removing the old ones anyways

3X2

I believe you have to use either the heat riser or spacer. Isn't the manifold flange flat for a gasket and not chamfered for a donut? I've been running a spacer and 67 BB side exits for over 40 years without any issues.

CanadaGrant

The exhaust manifold is flat. The riser (or spacer) has one flat side that uses a normal gasket between it and the manifold and one beveled or curved side to match the donut and flange plate. You have to use one or the other as you can't use a donut gasket against the flat exhaust manifold surface.