I want get the exhaust done on my 79 crew. Now it has 2 1/2" duals. Each with one 8" no name muffler. And they dump a little behind the back axle. The truck is annoyingly loud and I really want it to get a little quieter. I don't want just stock can't hear anything exhaust but not too loud either. The local muffler shop says that they can install a pair of magnaflow mufflers for $150. Is that a fair deal? Will that quiet the truck down? Secondly, will installing an h pipe help this motor? I'm pretty sure it's stock aside from a 4 pot Ed and a weiand intake. The way it sets now idle is pretty good but 2000 and up is kinda obnoxious and I really want it a little quieter.

 

$150 for a pair of Magnaflows is a good price. But which ones? A 20-inch straight-thru perforated core is about $80. Btw, the longer the muffler, the lower dB they tend to be.

Because your tips dump under the truck, you're probably experiencing reverberation and sound pressure waves being trapped by the nooks and crannies of the bed. Terminate the tips laterally beyond the body line to allow the sound waves to escape.

 

I think that is fair for Magnaflow's.....Flowmaster's are more $. To get the sound out from under the truck and quite things down a bit, either run it out the back, but that still can be loud. Best way IMO is to run it up over the rear axle and then turn it out behind the tires.

H pipe is a good idea to help balance the exhaust tone.

 

Ok so right now it's got 13 1/2" flowmasters. The magnaflows he showed could definitely been 22" long. Would that quiet it down much? Also, how much real world performance would a h pipe give me? As far "tone" I probably won't be able to tell a difference anyway. Would exiting under the back bumper help? As far as behind the tires go I think that is butt ugly. And for before the tire, I think that looks good but sometime soon I'm gonna build a flatbed for it and that's where I was gonna put my tool box.

 

I would think more muffler more exhaust is muffled? The straight out the back can work, but you can get some reverb against the back window when traveling a highway speeds, depends on the tip angles.

Since the behind the tires is not an option, you could be a temp in front till you get the boxes on. Or change the current tip angles to see if that helps first.

 

Getting the tips outside the body line really helps with noise. You could probably dump outside the bed in front of the rear wheels.

As for mufflers, I like "turbos". Not too loud cruising but let you know they are there when you get on it. Generic turbos are really low cost... at the higher end, Dynomax in a bigger case wold work well. Lots of choices.

 

Yeah, I also like the "Turbo" mufflers on my '77. Tips up over rear axle and out to sides at rear corners of bed.