Most accurate L56-57 heat riser?

[Gary C.]

Re: Most accurate L56-57 heat riser?

Alex, you should be able to tell if your exhaust header pipes are welded to the flange or if there's a slip flange and a doughnut used without taking anything apart. 56 & 57 frame differences are in the 5th edition 56-7 JM Chassis section. Gary....

[Edward M.]

Re: Most accurate L56-57 heat riser?

56 exhaust header flange is flush and welded to the exhaust pipe. Very late 56's more than likely had the '57 heat riser muffler system with the doughnut and non-welded header flange. Same as most had '57 frames.

Since Alex's 56 is a late car it will be interesting to see which type of heat riser his car has - flush or doughnut type?
Gary....

I have a friend with a mid August build 56 that has the 56 style exhaust pipes (flange welded to the pipe).

Alex, look and see if the 3 bolt flange on your exhaust pipe is welded to the exhaust pipe, or if the flange is a separate piece that slides up and pulls the exhaust pipe tight against the manifold. Should be the same on both sides.

If you are looking for a 56 3 bolt heat riser, that is going to be a tough part to find. As best I can tell, it only came on 56 Corvettes and 2x4 passenger cars.

I seem to recall that someboby was rebuilding / restoring heat risers. Anyone know who that might be?

I also wonder if anyone can tell the 56 from the 57 once it is installed. I "think" the 57 heat riser would work OK with the 56 pipes and manifold.

[Gary C.]

Re: Most accurate L56-57 heat riser?

Ed, have seen several original unrestored 56's VIN #'s above 4000, that had their original 57 style exhaust with a 56 engine. Also have seen one of the first 25 57's that was unrestored and it had a 56 frame. Some of the very late 56's and early 57's were produced simultaneously on the assembly line. Gary....

[Edward M.]

Re: Most accurate L56-57 heat riser?

Ed, have seen several original unrestored 56's VIN #'s above 4000, with the 57 style exhaust with a 56 engine. Also have seen one of the 1st 25 57's that was unrestored and it had a 56 frame. Gary....

Interesting. Now once Alex tells us what he has....

[Alexander C.]

Re: Most accurate L56-57 heat riser?

I'll check it out tonight when I get home from work...

Thanks!

[Edward M.]

Re: Most accurate L56-57 heat riser?

I'll check it out tonight when I get home from work...

Thanks!

Alex;

What is the verdict? What do your pipes look like?

[Alexander C.]

Re: Most accurate L56-57 heat riser?

Here is a pic from the rear next to the starter looking up towards the front and the hear riser. You can even see the original red paint on the side of the engine block

Verdict, welded flange

[Edward M.]

Re: Most accurate L56-57 heat riser?

Then I would say you need the 56 heat riser, not the 57 and later heat riser.

UNLESS, they cannot be told apart once they are installed. Hopefully, someone knows the answer to this.

[Alexander C.]

Re: Most accurate L56-57 heat riser?

Ok, thanks! I'll keep an eye out for a 3 bolt '56 heat riser.

I think when I remove it I'll just be really good about soaking it long enough in Evapo-Rust and MMO to try and bring it back to life. I'm just not sure if that spring will ever be working again at this point...

[Edward M.]

Re: Most accurate L56-57 heat riser?

Ok, thanks! I'll keep an eye out for a 3 bolt '56 heat riser.

I think when I remove it I'll just be really good about soaking it long enough in Evapo-Rust and MMO to try and bring it back to life. I'm just not sure if that spring will ever be working again at this point...

That sounds like a good plan. The spring can be replaced. Keep your eye out for a good original style replacement.

[Gary C.]

Re: Most accurate L56-57 heat riser?

Remember, there are two springs. The big coil spring and a small wire spring. Gary....