Sad story. One of the after market (Midas?) mufflers on my 1963 coupe developed a split so I decided to replace both sides of the whole system since the car was suspended on jack stands in my garage.The original heat riser could possibly have been restored but I chose to replace it. I ordered a complete system from Corvette Central in Sawyer, Michigan which included a heat riser. The fit of the new riser seemed a little snug and I used a deep well socket to persuade the new riser into position. Unbeknownst to me, the pressure on the manifold studs broke the manifold at the stud closest to the block. After receiving a new aftermarket replacement manifold ($219)from Corvette Central, I test fit the new heat riser on the new manifold and studs, and found that the riser did not fit. I called Corvette central asking for an explanation. Their representative and I compared micrometer measurements between their new part and my original one. The holes on the new riser were .10 inch too close to each other compared to the original. I modified the new one and installed it. To my surprise, the technician I had spoken to called me to report that he, and others had assembled several new combinations of risers and manifolds that they carry and discovered that all of the risers they carry would not fit. He told me that their supplier would be contacted and when the problem was resolved that they would send me a new one. Since I forced the heat riser into position on the original manifold, breaking it was my fault. I assume that Corvette Central won't ship heat risers with the same issue but other sources of parts may use the same suppliers of risers as sent to Corvette Central. By the way I never throw the old/broken parts from my C2 away.

 

It seems many repro parts are a bit off....and the poor buyer has to deal with it. With me recently it was a water pump rebuild kit, others have had steering box kit issues (I too may have that problem - not sure yet)..

 

That's a good reminder to double check all repro parts against the originals especially if you have to use a foreign replacement. Unfortunately, mm's and inches differences continues to be a problem with many parts, things are just slightly off and slight modification for better fit is common. OP, it should be possible to repair your original manifold if you can find a good welder in case you want to save it. Also, many here run without a heat riser butterfly. You can remove it from the housing or wire it open and reuse your original one. I removed mine and run the car in the Northeast in cold weather with no problems. Left the counter weight for appearance, it is drilled and safety wired. Pilot Dan

 

Thanks for the replies!

The original riser was caked with carbon and the butterfly wouldn't move even after application of penetrating oil. It was frozen in the 1/2 open position. Not surprised though. The car sat in my parents garage on blocks since 1981 with out being started or driven. I rebuilt the carburetor and it started the third time I cranked it over. Oh yeah, everything that had liquid in it, except the carburetor, has been replaced. It shimmy's at about 65MPH and I'm suspicious of the alignment or suspension wear. Mileage is about 67K. I bought fake knock off wheels and red line tire package from Coker. I had the wheel balance checked locally and that is not the shimmy source. I'm in the Denver, Colorado area and I need to find a shop I can trust to check the suspension.

 

I would recommend you start a new thread, as you are way off subject and the local owners may never see your problem.
Also, you can title the new tread with Denver shop to give some guys a hint of what you need.

 

I would send a PM to Lars. He's just North of Denver in Lafayette and without a doubt knows someone in your area that can help with your problem.

He also happens to be a resident carburetor and distributor Guru here on the Forum and an all around good guy to talk to.

By the way, welcome to the Corvette Forum...

Good luck... GUSTO

 

Greetings GUSTO,
I was able to find LARS email address from one of the threads you suggested. Lars says he responds to email fasted than the forum. I'm contacting him today.
Thanks,
gaczewski

 

 

They must have sent the manufacturing specs over in English instead of Chinese.