Inliners International Forums General Discussion Engines Split exhaust

I've seen Chvey 235 exhausts split 2 different ways: one way the manifold is cut in half, the ends are blocked off, and a new flange is welded on (like 12 Port Advertiser Kansas Kustoms does it). The other way, the manifold is blocked and a flange is welded on, but the manifod isn't cut into. Is there an advantage/disadvantage to one type over the other? Is there a difference in sound?

Thanks,
Joe

Ive been thinking of getting some Plate steel & weldable iron pipe Making my own split system .
thinking of doing what you are talking about scares me somewhat , seems like it would be more trouble to retro cast iron .

Gentlemen;

Muffler shops have been doing that for years.
Sometimes it works & sometimes there are problems.

I would buy the Fentons from Partick's as they always work great.

Good luck, John M.,3370...

The first split Chevy offered was the one in the 53 Corvette and it was a one peace model with a internal block of plate. The good thing is, it is verry rigid and can be bolted on with the intake verry secure. The bad thing is the price 300$ like the one on ebay in the moment to 575$ that i saw in a corvette shop.

Mike Yoder of Kansas Kustoms does a split for me and I have to say it is a great peace of craftmanship and I would do it any time again.

The sound is great, it looks vintage (almost stock) and it keeps the heat riser so you don`t have to go with the ugly heat plate and tubes as you need for the Fentons.

There will be no notable difference in sound and performance between the two models.

Talk to Mike, he will do a great job for you and it is the cheapest way to get a split.

Frank

I did the two piece split thing on my 261 and I have been running it for about twelve years with no problem. The disadvantage is they are hard to install when you have an intake manifold and two exhaust manifolds to install at the same time. Not enough hands. I cut the heat box out completely and moved the cast iron exhaust flange to the bigger end of the runner between the ports. Then cut a cast flange off another manifold and put it on the other runner. I installed dowel pins into the inside edge of the flange where the manifold meets the head. And drilled short holes in the head for the dowels. This helps hold the inside ends in place.

If you do your own, Good Luck.

I have been splitting inline manifolds (not just chevy )for over 40 years and had no problems to date. In fact (in my opinion)the splitting the stock manifold has advantages. In addition to the mentioned heat riser useage and alignment problems, when the manifold is blocked, a hole can be added to the block plate to control the "rack"sound( some like it,some don't) and the harshness or tone of the system.I did a lot of these with a cracker box welder and Nickel rod and it helps to pre-heat the manifold
in a oven or simply placing it on a charcoal grille for a while.---Paul

I never heard back from Mike Yoder, so I got a one piece split manifold from someone in IN (cheaper, too). It looks great, but the problem is that he removed the heat riser "flap" and spring. Before I send it back to him, is it necessary to retain that flap and spring? heat will still be getting to the intake manifold (right?), but will it eventually make the intake too hot? This is going on a year-round daily driver so it needs to perform well in 90+ degree weather as well as sub zero weather.

Thanks,
joe

Heat riser flapper, FLAP! My local manifold expert has been splitting Chev manifolds for decades says, "weld the flapper in the position to direct the exhaust down, not up to the intake".

OK. This manifold has NO flapper whatsoever. Will that be a problem? i imagine flow will be better, but what about cold start ups, heat, etc?

If it were mine, Id have the flapper welded back in, or another piece of metal to deflect the heat. Wouldn't worry about the spring at this point.

Right now i am tearing apart my 66 Chevy Bel Air and when i pulled the exhaust manifold i saw that my "heat flapper thang" was stuck. Like to the point where huge vice grips and wd40 wouldnt even move it. Took the torch to it for a bit and got it out. I put it back together real quick and took it for a drive and felt like an idiot for not checking it sooner. Car ran alot better than when it was stuck in the fully closed position