ive been runnig my 350 with open headers for the past five years now, is that harmful to the motor because there is no backpressure?

 

backpressure is a debateable concept that people have been discussing for many years now.The only way it could harm it is if somehow you got cold air sucked through the headers and that could hurt your valves,thats just about it.

 

Nope, open headers won't hurt the engine at all. Backpressure in an exhaust system is more of a performance debate, as Ali stated.
You could do some harm running the engine with no headers/manifolds at all. That's where you could suck in some cold air and warp a valve stem from the sudden change in temp. The opening of the headers is far enough away from the valves to be concerned about.

 

Your lucky, i would be pulled over in a millisecond if i went open headers!

 

i have a question i wanna get electric cutouts do they come in a pack of 2 also how do they work it just looks llike it would close the exhaust up and not do anything.

 

i believe the way they work is theres a flap that switches it from going through the muffler to just coming out of an open end

 

There are two channels on the the end of the cutout one runs to the exhaust the other is open with a butterfly valve, much like a carb. when you flip a switch the the butterfly opens basically running open headers. you can get them in sets but be prepared to spend about 500 bucks.

 

ive done dyno testing at school and we switched between open header, 6,12, and 18 inch extensions, bullet mufflers, and turbo mufflers. the most hp was produced with the 6 inch extension. the most torque produced was with the 2 mufflers. although the top numbers were only different by a few digits on our mules, the power band was completely different. at specific rpms, open headers had as much as 60 lb ft less than with mufflers.

now as to whether it will hurt the engine, no it wont. will it hurt performance, yes. and our test mules were a 454, 460, and 440 hemi