Tri Mill mufler

I just bought a tri mill muffler for my 78 intermeccanica speedster, with a 1600 dual-port webber set-up...will I have to change the jetting ? It will be mated to stock headers/heater boxes....are these mufflers any good ? Thanks Tom

your first problem could be, does it fit....they are not necessarily just a bolt on.....a few guys have had problems with the body getting in the way....

Ditto on what Vince says. Make sure you get the Bus (Type II) version of the muffler; that one is supposed to fit Speedster replicas. They are very good systems and look great on Speedster replicas as they look very similar to the original Porsche exhausts. Their tubing is 1-1/2" in diameter as compared to the 1-3/8" in exhausts meant for stock engine applications. I suggest you install it without messing with the carburetion and try the car. If it doesn't perform well then you can start tweaking.

Ricardo, where to get more info on the Tri-Mil?
The sites I found that had any, didnt show pics. I want to know;
Can connect to bus heat exch (trapezoidal flange), or only to the Tri-Mil header?

http://community.webshots.com/slideshow?ID=520357846&key=GGCWSZ#
CMC/'74 VW with 2.0 L hydraulic
best heat this side of a BN4

Dave; the muffler fits the engine just like a stock one does; if using your stock heat exchangers just route the fresh air hoses from the fan shroud directly to the heat exchangers through the holes in the rear engine tin.

Ricardo - I read in another post that you went for bigger 1 1/2" heater boxes. Did you have any problems with them matching up to the stock VS muffler system? My limited understanding is that the stock VS heater boxes are 1 3/8". If the VS muffler has 1 1/2" tubes how do they work together? I plead ignorance!

Yes Brad you're totally correct. The thing is that the Tri-Mil is made so that you can use stock 1-3/8" heater boxes with the crummy leaky clamps just like with a stock muffler where the heater box fits into the muffler's flared ends. I had to get a muffler shop to modify the Tri-Mil for me by adding two flanges (included with the 1-1/2" heater boxes) to the two lower tubes since the 1-1/2" heater boxes have the flanges. Luckily my friend and fellow SOC member Jjr has a spare longblock that we took to the muffler shop in an engine stand to be able to mock up the exhaust system installation (heater boxes and all). It took some heating and tweaking of the two upper tubes (coming from the cylinder heads) in the Tri-Mil to get it to mate perfectly with its new lower flanges to the flanged heater boxes. It was a shame because the ceramic coating went south on the spots that were heated with the torch. All I could do was paint over those spots with heat resistant paint. Everything's ready to bolt on when I pull the engine out to swap the heads for big valve ported ones along with some nice valve train components from Gene Berg in about 2,200 miles.