Purpose of 2.5" sleeve to downpipes?
 

I have Ramhorns with 2.5" outlets, and 64-65 2.5" downpipes....

Do I have to use the 2.5" sleeve shown in the images below? (Between the donut and the downpipe?) I'm going to go check to see how it bolts up without it, but I thought I'd ask also.....

https://www.corvettecentral.com/c3-6...c2%26count%3d9

https://cimg6.ibsrv.net/gimg/www.cor...3b7460b80d.jpg

The purpose of the insert "sleeve" was to prevent you from burning the packing out... Always use them! It will bolt up fine without it, but it acts as a barrier between the hot exhaust and the packing.

Ernie

Look here:
https://www.castheads.com/manifolds-...pes-pipe-kits/
One of these kits could be adapted to eliminate the packing and sleeve
Not cheap, but you would have a true 2 1/2" exhaust.

The packing is the insulator between the pipe and the manifold. Everyone has it... what they don't realize is that the packing will last you way longer with the insert in there, either 2" or 2.5. I'm not sure where they got the name of "donut gasket", GM always called in a packing.

Willcox

Thanks :)

Because it looks somewhat like a donut?

Thanks for the info. Guess I'll use the sleeves..... good thing I've learned to ask around here instead of just ASSuming things. :D

I like the "Donut" gasket term.... communicates the information and provides a visual description in your mind.

So far it looks like those 2.5" 64-65 downpipes are going to fit quite well into my 68.

Yes, I think its the better term for allowing people to figure out what it means from context.

I don't eat donuts... :hide: lol