Heat riser...

[silverstude]

on a 350 SBC. I want to remove it, but there are 2 sizes. The listings are for corvette 350 and a smaller one for a 2 barrel engine. I know the 70 supposedly had a Corvette 350/300, but my exhaust headpipe is only 2".

Has anyone gone thru this before?

thx

[WayneC]

,

on a 350 SBC. I want to remove it, but there are 2 sizes.

I can't answer directly, but most 350ci engines take the 2" valve, so that's most likely.

Since you already know your exhaust pipe is 2", a larger heat riser bore would do nothing for performance anyway.

The risers are available from most parts stores (check your local ones), so you could remove the old one

and measure the bore and then drive to the parts store to get the replacement... they may even let you

take both sizes in advance and bring back the one you don't use.

https://www.summitracing.com/parts/oer-3887023

[Avanti83]

There are corvette engines and then there were CORVETTE!! engines. The 2 1/2" exhaust were only supplied on a few engines and years IIRC. Usually they were on the HiPO 327's from the 60's. They are available aftermarket from a number of sources for under $60 usually.

I'd be surprised if yours were 2 1/2" unless somebody changed them.

Edited August 12, 2016 by Avanti83

[wildfelr]

RQB3263 1981 / 305...I did this a year or so ago....if your talking about the flapper valve in your exhaust manifold.....removing it is a worthwhile project...anything to remove restriction, improve overall flow, and get the heat out...(1) remove the manifold (2) cut out the flapper valve and cross shaft. a bit difficult as there not made to be removed, a friend w a cutting torch would make it easy (3)weld up the cross shaft hole (4) reinstall manifold...done...good luck....RQB3263

[wildfelr]

RQB3263....BTW the valve is actually in a separate small unit from the manifold ,,,you may not have to remove the manifold if you can get the pipe down far enough to remove the valve assy....replace the gaskets while its apart...i was not able to get the valve out without removing the bolts from the manifold, the studs interfered ....a lot depends on how far down you can move the exhaust pipe..mine wouldnt move far enough....RQB3263