The following information was originally posted to the Amphicar-Lovers List by the inimitable Tommy Sciortino (aka. "Tommy in Tampa"). In view of its potential usefulness to any Amphicar owner who's ever suspected that his or her engine may be the same type later used to power the Tickle-Me-Elmo® doll, it is reproduced here for posterity and easy reference.
Hi guys! I posted this before but it may be worth reading again. Do you want to make an improvement in your car's performance that is affordable, fits perfectly, looks stock and WORKS GREAT? This is what you can do: Call Gordon Imports, ask about the cats, then order: one high performance muffler, one H/P "J" pipe, a gasket for the "J" pipe, three threaded studs with copper nuts and an exhaust manifold gasket. OK, remove the exhaust manifold, if you're lucky you can wiggle it out with the muffler attached. Then what I did was take it as-is to the NAPA machine shop, where they did two things: 1.) removed the studs and "surfaced" that area before installing the new studs 2.) "surfaced" that area where the manifold bolts to the head. Now you want to polish the inside of the manifold. You can use a Dremel tool or whatever you have, but the smoother the inside is, the better it will work. Don't be afraid...You can take a lot of metal out of the inside if you have the time. The smoother the inside is, the better it will work. Now when you receive the "J" pipe and muffler, if for some reason they are not the same size, just take them to the discount muffler shop of your choice and have them stretch the "J" pipe so it will fit snugly into the muffler. Put it back together, tighten the bolts on the manifold. The sequence is to start in the center and work towards the ends. I make three passes, so I repeat the sequence three times to fully tighten the bolts. When you reattach the "J" pipe take some flat stainless washers, grind one edge a little flat and put them on the stud before the copper nut. You may not need a clamp at the muffler if you have a good fit. If you do need a clamp, get one that is called a "360 degree clamp."
Hold on to your hat: You are gonna notice a BIG difference in the performance and your Amphi WILL RUN A LOT COOLER!
Just trying to be a team player,
Tommy in Tampa
P.S. If you follow those copper nuts with a couple stainless nuts on each stud, you will always be able to remove them in the future. Also, if your engine is running hot, and it gradually keeps getting hotter the longer you run it, then the fins of your oil cooler, located between the radiator and the engine, might be stopped up.
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Last updated May 07, 2013