I am building my 70 blazer and it will have a 350. I will be towing my toy with it. I want to beef up performance with a shift kit in the auto and 2-2.5 exaust and was thinking twards headers also. But then I started thinking about 5-15 hours of ratty exaust as i drive down the highway. Are say block huggers any quieter than full headers?

I don't think that block-huggers are any quieter. Big difference would be in muffler selection; maybe try a 70-series Flowmaster. You could also try these http://www.carchemistry.com/ccinserts.html with mufflers.

Yeah the difference is defintely in the muffler. Get a "turbo" style muffler. Usually any muffler (that I have used) that is designated as "turbo" will cruise quietly but it'll get loud when you reallly open it up.

The question should be, Do they make headers that don't leak.:skull:

I believe that Sanderson makes a cast header for both small and bb chevy's. I think they want big dough for them, but being cast they would probably be much quieter.

I have headers in my '70 pick-up and it isn't much louder than my '96 on teh highway (exhaust wise, lots more wind noise in the 70) I would run high quality headers, with a thick flange, flowmasters, and run the pipes out the back. My old '70 Blaze had the exhaust routed right behind the rear tires, and it way louder at highway speeds, than my pick-up, even though it had ram horn manifolds on it.

Route the pipes out the back, and keep everything sealed up and you will be fine:)

I don't think you can use Quite and flowmaster in the same sentence! :D

There is some good info here:
http://members.tripod.com/~racetruck/muffler.html

My understanding is most of the "header noise" is on small-block Chevys with cheapie headers. :flipoff2:

Pony up for the good 14 gauge headers and they're not any louder than manifolds - assuming you run a muffler and full exhaust, of course. :D

thats a killer link. I was thinking of the elderbrock mufflers anyways. It's also good to hear that a header can run quiet with the right muffler and still have the performance advantages that I am looking for. I am thinking headman.... Anyone got better ideas?

I'd pay the extra $$$ to get the "aluminized" headers. I use to only get 2 years out of a set before they would rust out at the collector but I never bought high dollar ones either (your milage may vary:D ), seems like my headers would always go right when I was strapped for cash too.
Where you have your exhaust exit has a lot to due with noise as well. Straight out back by the bumper gives anyone following an earful but it's still pretty quiet in the cab.
Also get a GOOD set of header gaskets, the ones with stainess in the center and gasket material on each side. I bought a set for $20 that lasted through 4 sets of headers and never leaked.
I've heard good things about "collector doughnuts" but I've never tried them myself. Someone once told me a BBC manifold doughnut will fit a 3" collector.

Edit: I personally HATE SBC headers after having them on the last 3 cars I've owned. Having to remove 3 (I think it was 3, maybe more) spark plugs with a box end wrench and having plug wires burn up got old really fast. I'm sticking with manifolds from now on.

'Doug Thorley' makes damn fine headers, but they have gone through some management issues in the past year so call to see if they have anything in stock. Get headers with at least 3/8" thick flanges and they won't leak from heating and cooling. My full lengths in my EB have 1/2" flanges. the bigger the better.

Eric

I had Hedman long tube headers, 3" hi-flow cat, and a Dynomax 3" SS Ultra-Flo mufller under my 460 Bronco and it was too quiet for me :) I've since removed the muffler and it's just right now.

I figured this thread may get a few miles under it...thanx...

I hate headers....they are just a PITA because of dealing with the leaks. I believe that Edlebrock makes what they call "high flow exhaust manifolds". They have nice heavy flanges like a factory manifold but they flow closer to a tradition header. I would go that route so you don't have to retorque the damn things every oil change.


just my .02