3.5” single exhaust

[travis]

I bought another project this weekend, because I didn’t have enough to do already It’s a 1987 F-150 extended cab short bed, body is in perfect shape but the paint is pretty bad. 351w “HO” (lol), C-6, 3.55’s...it’s just a 4 year newer version of my ‘83. Drives great, engine is very tired. Apparently my idea of “runs great” is very different than other people’s...

I was kind of pissed off that the pictures and description was misleading, especially after driving 1.5 hours one way to go see it. It’s definitely a 50 footer. The owner made it clear that he really wanted it gone, so off the cuff I offered the going rate for running 351w cores around here and he accepted it. The C-6 feels good, the engine runs but has very little oil pressure, almost brand new Goodyear tires all the way around, American Racing aluminum wheels, brand new 670 Holley street avenger, and lots of other new parts. I drove it home for $600.

I’ve got a 395w here that needs freshened up, probably 400-425hp, that I want to put in it. 10.1-1 compression, 222/230 hydraulic roller, TFS 170 heads, etc. I’m thinking of doing something a little different for the exhaust. 1 5/8” Doug’s tri-y’s, 2 1/2” from the collectors to a dual 2.5” in/single 3.5” out y-pipe, then 3.5” back to a big 3.5” in/out Walker megaflow RV muffler, and a single 3.5” tailpipe. I want a relatively quiet but still aggressive sounding exhaust. Will this system be sufficient? The truck has dual fuel tanks so you can’t a exhaust pipe down the drivers side.

[F-BIRD'88]

It should work well. Similar to what many 3rd gen F body cars use.
If the muffler turns out to be too aggressive, you can change it. ( personal taste) You need to look into supercharging your Windsor motor combos for these big old trucks. Lots of good ways to skin that cat.

[Orr89rocz]

Stock gm 405 hp 6.2 comes with similar setup, 3.5” single. I put an ultraflo round in mine and sounds quiet but nice and deep

[travis]

It should work well. Similar to what many 3rd gen F body cars use.
If the muffler turns out to be too aggressive, you can change it. ( personal taste) You need to look into supercharging your Windsor motor combos for these big old trucks. Lots of good ways to skin that cat.

Unfortunately a blower nearly doubles the cost of the build...it’s not in the budget. I will have one some day though

[travis]

Stock gm 405 hp 6.2 comes with similar setup, 3.5” single. I put an ultraflo round in mine and sounds quiet but nice and deep

The round ultra flow was what I was thinking at first, but I don’t have cats, so it may be a little loud.

[Orr89rocz]

I have used many ultra flos in 3” to 4” diameter, and love them. They generally arent that loud. Now on a 4” single 383 that was making 500 hp 11:1, it was loud but not as bad as a bullet or borla xr1

If you want can always add a bullet upstream somewhere and then the ultra at the end. The big fat and long case is most quiet

[groberts101]

Yes it will be sufficient if you run a straight through type muffler but that Walker will give up power due to its smaller ID internal flow tube. Just bought one for my boys F150 and had to pick the big RV version to get 3" inners. Personally, I generally prefer a chambered style muffler over glasspack style but you need to be very diligent about determining internal flow tube sizing before ordering. 3.5" in/out means almost squat when the internal flow tube is size capped at 2.5".

Edit.. nm.. should have looked at that model first.. appears to be straight through design.. not chambered. Only downside to any of those straight through packed designs is oil/carbon accumulation of packing over time which inevitably makes them get louder after a year or 2.