I am in the process of putting a 351w into my project truck (full disclosure: its a 47 half ton, not an 80-86, but the engine is from an 82).

The engine has an edelbrock carb, edelbrock intake, compcams camshaft, and headers.

I want it to sound deep and I want to hear it, but I don't want it to be crazy loud or obnoxious. Truck is going to be a cruiser/fun truck.

My questions:

Should I go with dual exhaust? What are the advantages/disadvantages?

What are some good mufflers to use?
What kind of performance gains do you see with mufflers?

I am on a budget so I want to be money conscious, but I don't want to buy crappy mufflers.

 

I suggest researching on the muffler companies websites, most of them have sound bytes that you can listen to their mufflers, for instance if you don't want loud and obnoxious stay away from the Flowmaster 40s, but the 50s maybe more to your liking, or some of the Thrush mufflers. And if it is a cruiser, duals or a large 3" single should help you with the upper end and not drone you out and cause a headache on every cruise. Lastly you didn't mention but are you planning on running stock exhaust manifolds or headers?

 

I am running aftermarket shorty headers

 

I will tell you that the Heartthrob welded HVS "Velocity Series" is a VERY GOOD sounding muffler with a deep tone once broken in and it does not have the annoying drone Flowmasters sometimes have thanks to the double wrapped shell. They make a "deep tone" kit that to me looks like glass packs and I'd avoid those. I put their single 3" cat back kit (along with new y pipe and single cat to replace the duals) on an '86 I redid for Dad and was initially disappointed. Visited several months later and was pleased with how it came around. Wish like hell I had know that the Iron Rock kit for Jeep Cherokee was made by Heartthrob before I bought the Dynomax kit for mine.

Personally I think split true duals are a great sounding setup with a decent cam, but the worst performing due to scavenging loss. Just did a roller cam 300hp 302 swap into an '84 4x4 that already had split duals off the manifolds with bullets on it. The owner also bought 1-5/8" long tubes (mistake I thought) to attach to the existing pipes....had to be run under the tranny crossmember instead of through it like they were originally. It sounds pretty good but I think they should put at least an H connector between the pipes for scavenging.

'66 Impala with Heartthrob HVS mufflers

'77 Bronco with Heartthrob turbo mufflers

 

I cannot find shorty headers for my 85 351w.. only long tubes. Seems to be elusive

 

If you're going to put in new head pipes anyway, I think 5.8L Mustang headers fit.

Summit has shorties listed for '86-'96 5.8L F150 that say they bolt to stock y pipe. Can't imagine what's different other than TV cable on '86-up vs TV rod but I wouldn't think the rod is close to the exhaust either way. If you have an '85 with EFI maybe they're perfect.

 

No AOD behind a W, they were C6 only in trucks, so he is golden there, the C6 kept a kickdown rod on the W until 88.
On my 460 truck due to packaging and long tubes my exhaust runs to the passengers side right off the header, and then up over the crossmember, and the rh side goes up and over right off the header as well(getting things up where they wont get torn off is more important than power on it.) Due to the considerable difference in pipe length, a crossover or x pipe is not practical on my truck, but I do run a dual/dual magnaflow with their true-x core, which is essentially an x pipe inside.

 

Its an 85 with a carb. I may just stick with manifolds. Not sure headers are even worth the money