Exhaust :Modifications will this work,355 to a 348

If you can weld then the fitment means nothing. If you want to know what happens inside then I would use a vacuum on the various inputs and outlets to determine the flow and if I would be happy by covering the "goose neck".

 

I'm pretty sure the adaptation will require a lot more than this.

 

What are you trying to accomplish?

The 355 and the 348 share the same basic header design, minus the bypass pipe "goose neck" of the 355. They are both a tri-y/4-2-1 design, they both have the primaries non sequentially paired (1-4/2-3), and they both have short primaries and shorter secondaries. That and stock 355 headers are notorious for melting down. Also the 355 headers have the secondary injection piping welded to the primaries, where as the 348 does not (the 348's are bolted to the exhaust ports on the head). If you are trying to make more power, in my opinion, there are better header designs than stock.

 

i did it...I lopped off the gooseneck and welded it shut. I did continue to run my bypass valve, but I had it routed to straight pipe...like one would see on a wastegate on turbo car. (So the primaries went through the exhaust. the secondary was a straight pipe)

Makes the valve actuation much more noticeable. I wouldn't go through the effort, though. Just get a challenge exhaust (if you can handle it) or go with the other usual exhaust systems.

 

OH, the muffler!

Lol!

D'Oh! Did I totally misread the original post or what.

 

I guess he has a 348 but wants to use a free 355 muffler and weld it so that he can use it on his car. beats me!

 

Well since it's a free muffler, and he can weld, why not? Maybe he should test fit it before he cuts and welds it. I'd be interested to see pics of how he did it if it works.

So are you gonna try it Fazio?

 

What's the goal? The gooseneck portion bypasses some of the internal baffling for less resistance and more noise. Bolting it on without the bypass would result in probably what would be close to stock 348 noise if not a little queiter. What I would do is tie the gooseneck portion to the other two inlets rather than block it off so you'd get similar to 355 noise on bypass.

 

+1 .... it would be better if they just welded up a magna-flow muffler in there.