vortec heads

[td7172]

I am buying a 355 with vortec heads. I was told that I shouldn't run open headers because the vortec heads were made to run with a certain amount of back pressure. I should run some type of muffler. This truck is strickly for drag racing. What do you guys think?

[ZR1BLAZER]

i think that would be true for any head to a point. i never felt a difference in power with open headers and full exhaust with my vortecs?

[harleyboy]

here is a race muffler from summit dont know if it will help but trying.
http://store.summitracing.com/egnsearch.asp?N=400105+304582+115&autoview=sku

[td7172]

No power loss that you know of?

[harleyboy]

they are a free flow muffler like a glass but without the resrictions of a muffler.

[td7172]

Sounds good guys, thanks

[-Deception-]

I think your can run no muffler if you have a long exhaust pipe so you dont float a valve but I could be wrong. So how do people run exhaust cut offs they dont have back pressure.

[grimpuppy]

If it is drag only, you have long tubes and you don't have a muffler rule run open headers. If you have shorties, run extensions back a ways with turn downs so you aint blowing hot exhaust on your tranny. Back pressure don't float valves, bad or wrong valve springs do.

[td7172]

So regular headers with a 12" tube ext. turned down should work?

[ZR1BLAZER]

yep. it will work.

[td7172]

Thanks again guys, damn I like this site!

[grimpuppy]

Will work just fine

[stroker1]

Exactly as they said, shorties need extensions and then turn downs. You can run turn downs right off the collectors on long tube headers. Biggest benefit to a race muffler is not as much noise. Like a Dynomax Bullet muffler, they sound great but I don't think they would make a real noticeable difference in power. I have long tube fender exit headers with turnouts and I love them for drag only, but they are very loud.

http://www.s10v8.com/picture.php?albumid=5&pictureid=75

[Dagget427]

A trick i've been told works ( haven't tried it myself ) is run straight pipe from your collector with a crayon mark along the length, run the motor, where the mark burns off is where you cut the pipe.

[ThomasAlexander]

Holy crap! That's awesome! I bet the heat from your header heats the tire up and makes it more sticky too!

[td7172]

Thats the way they did it years ago and it worked. Grease the inside of the tube with axle grease as far as you could reach. Make a couple passes. then cut the pipe where the grease dried up from heat. Some of the old tricks still work. You need to listen to the old drag racers!!