I'm thinking about getting some electronic exhaust cutouts for my 65' GT. They should give me a little more power.What do you guys think?

 

I wanna do the same thing. You dont need to modify your existing exhaust do you?

 

Unless your running BB power I think exhaust cutouts sound like ****.

I have a buddy that has the electric cutouts on his 67 RS 502 and it sound "ok". And if im not mistaken running open header can actually rob a little power from you.

Im sure thumpin and some of the other guys can clarify.

 

Motors get tuned...meaning, you tune your motor for your exhaust.
So you will either, tune your motor for your regular exhaust and you will no longer be optimal when you 'open' the cutout, or you will be tuned for no exhaust meaning you will run sub optimal when you have them closed.

IMO, electric exhaust cut outs are to vintage automobiles what yellow seatbelts and/or stickers are to modern imports. The only valid use there is for them (again IMO) is to show off at car shows.

Try not to burn a valve doing it

 

+1, and also the "tune" of your exhaust sound means that your system is reaching AT LEAST far enough back to go through mufflers. With open exhaust, all you'll get is an untuned obnoxious, snap-crackle-pop note.

 

It depends on where you put them and what your exhuast is like. If you put them at the back, but ahead of the mufflers, then it will have the loud straight pipe sound. The popping and cackle comes from too small of a pipe being used, and because it now has a rich mixture being dumped in the exhuast on some cylinders. Use a 2.5" pipe on a 289-351 and you wont get the cackle, use a 1 7/8" - 2 1/4" pipe and you will get that without mufflers, and sometimes with.

The chances of burning a valve with an open header is minimal, but an exhuast leak at the head or no manifold/header at all will almost ensure you burn one, especially in cold weather. The valve cools down too fast and not in a uniform pattern when you have a direct source for cold air, like a header leak or a severely cracked manifold.

After 20" of pipe, there isnt much difference tuning wise, although the farther back you have the mufflers the better, and you can run large pipe into the mufflers like about a 3" and then a 2.5" over the axle and it wont affect the power that much. Plus with todays performance mufflers there isnt much gain from an open exhuast, now if you want whisper quiet mufflers that sound stock, then a cutout is perfect. Sorta the sleeper effect. With already loud mufflers a cutout just makes it louder inside the car, and the floor vibrates. lol..

I havent ever installed one on my cars, simply because I dont mind getting under it and taking off the entire system after the headers at the track. Its more of a weight issue anyway and I dont need the extra under it unless the track requires them. Sometimes I will just run the mufflers anyway, its easier on my ears and its less work before heading to the track. I see around a .1-.2 improvement by dropping the pipes, most of that is weight.

Up to you really.. but if you want them I recomend placement before the mufflers with a pipe exiting the side of the car before the rear wheels. It minimizes everything but how much wire you need to install them.

 

Yeah, there was definitely a gain in HP back in the old days when the exhaust system was not tuned at all. We drove our single muffler system cars to the track, then opened them up just under the driver and passenger door. We didn't have electronic stuff, just a cable that we pulled just before the race began. Today, I would not even think of opening up the system like we used to do. First of all, the modern exhaust systems are tuned from the engine back to the rear of the exhaust system. That creates a very efficient aspiration of the exhaust fumes while giving just the right amount of back pressure to the engine. Bottom line......dumb idea.