Will these stock ex manifolds seal off without heat riser?

[72farmer]

I have a 72 c-10 w/ a small block that I am trying to finish up. I am going to take my headers off and install stock manifolds.I am then going to take my truck to the exhaust shop to get new exhaust pipes ran all the way out back.I only have 1 of the heat riser valves.Can I remove the valves and get 6 shorter exhaust flange studs and do away with the valves?When I remove the valves there is a flat surface and not chamfered for the donut gasket to seal on.Will this work or do I need the risers to get the donut gasket to seal?Also are these the correct ex manifolds for my 72?

[El Dorado Jim]

the ones with the heat risers were for the passenger side, you have to use the valves...you can use the manifolds you have, just have to remove the flapper unit and shaft, then weld up or braze up the holes where the shaft was......I have done this in the past

[72farmer]

Both right and left manifolds have long studs like each side had a valve.So the flat surface without the valves will not seal on 3 bolt exhaust flange the exhaust shop puts on?

[68c10airstream]

Recall from about 30 years ago i think there is an exhaust donut for eliminating the heat riser. I believe it looks like a donut (that you eat) sliced in half and there is a metal flange that has been formed inside the throat and has 3 raised nubs that stick up and when installed the nubs grab the inside throat of the manifold and hold it in place till the exhaust pipe is installed. Obviously the drivers side gets the full height donut to fill in the recess in the manifold and leaves a raised donut to seal up against the down pipe. To sum it up when both sides are ready for a "Y" pipe to be installed BOTH sides look the same and if you didn't look close you wouldn't know the passenger side had a flat flange.

The passenger side will need shorter studs.

[Phildeez]

I found a felpro donut that was really tall at AutoZone. Then I was able to get it tightened down. I still have more stud than necessary out past the nuts but it works.

[71meangreenc10]

I had those manifolds a long time ago and no exhaust shop would do a bend because they dumped straight down and caused issues. My engine was bolted in the V8 location. You need the manifolds that dump at a 45 or 90 for a 2wd truck. LMC sells them new and it is worth it. I could be wrong.....

http://www.lmctruck.com/icatalog/cb/full.aspx?Page=153


Smitty

[hamjet]

http://www.ebay.com/itm/1957-1965-CH...08724708&rt=nc I just bought one of these for the 348. It's a blank, no flapper...

[GTSideSwipe]

This is what I did. I have one on my truck and I got a spacer off eBay.
http://m.ebay.com/itm/1964-81-Chevro...779?nav=SEARCH