What size Exhaust for 360FE

[Mikeincool]

I now have my '69 running. It has a 360 with new 2100 2 barrel carb. Everyone has said to put headers on before any other mods. So my questions is if I order shorty headers, what size pipes to run to the Flowmasters. I see that I can buy 2.5" or 3" mufflers. Does it depend on the headers? Sorry if this a well beaten head horse. I would think that 3" would give me the best flow. Does one size work better than another? It will not be a daily driver. Just a weekend cruzer. Also, Does someone sell a good exhaust pipe kit or is it better to make my own?

[1972hiboy]

I think dual 3 inch ex is going to be big for a 2bbl 360. Your gunna loose bottom end torque. I would go no bigger than 2.5 and would let you put a 4bbl on it in the future if you wanted to.

[Ranchero50]

A single 3" pipe would be overkill on a stock compression 360. Intake, cam and headers, 2.5 single might keep some torque on the chart. Engine runs out of revs at 4k due to low compression. 160 HP maybe 250 torque if left alone and it goes down once messed with. Dual 2" mandrel bent, maybe 2.25" with flat top pistons to bump the compression and a mild cam. Put an car 390 crank and rods in it and 2.5 mandrel bent. 428+ CI with good heads and you're starting to get to 3" territory. 95% of these trucks are over exhausted, lose torque for it. Lots of noise, not much music.

My '93 Mustang with a mildly blown 5.0 put down 390 rwhp and 390 ftlb or torque at 5200 rpm through 2.5" mandrel bent pipes That's about 450 at the crank. My '07 Jag XKR is rated at 420 hp and does it through 2.25" pipe. The later ones are over 510 hp from a blown 5.0l V8 and push that through the same 60 mm sized pipe. The exhaust note sounds like pure sex. Youtube some F type R exhaust videos.

Only time you'd ever go to 2.5" pipe is if you are paying an exhaust shop to custom bend your pipe because their crinkly bend style bender cost @ 30% of flow at each 90` bend. The more bends, the worst those pipes flow.

[Mikeincool]

Thanks for the info. I did not realize that going too big could hurt my torque. I would like to add horsepower later. For now I need exhaust with out leaks.

[Manny]

Thanks for the info. I did not realize that going too big could hurt my torque. I would like to add horsepower later. For now I need exhaust with out leaks.

Certainly can. You get to a point where the engine is having to shove the exhaust out the pipe. What you want is the sweet spot where the pulse of exhaust gases leaving the tube pull on the gases in the tube creating a scavenging effect. This makes everything much more better. It is a sweet spot though. Too little pipe chokes the engine. To big of exhaust pipe kills the scavenging effect.

[Ranchero50]

Thanks for the info. I did not realize that going too big could hurt my torque. I would like to add horsepower later. For now I need exhaust with out leaks.

Certainly can. You get to a point where the engine is having to shove the exhaust out the pipe. What you want is the sweet spot where the pulse of exhaust gases leaving the tube pull on the gases in the tube creating a scavenging effect. This makes everything much more better. It is a sweet spot though. Too little pipe chokes the engine. To big of exhaust pipe kills the scavenging effect.

Yes, then you can get crazy and do a decent X pipe and build an muffler that works exactly for your application and tune it for your sound requirements. This is the one I ended up with for my Jag. Started with the glass pack style bullets, added some reduced flow baffles to dampen the tone and then a pair of Helmholtz resonators to get rid of the drone. Took about a year of experimenting to get it where I like it. It's funny because due to the speed of sound changing with temps dropping it does drone more when really cold out.

https://www.jaguarforums.com/forum/xk-x ... 422/page4/

[RottenAppleRed]

Your best bet with stock compression and camshaft is to not go over 2 1/4" individual pipes from the manifold or shorty headers.

Option 1...duals with 2 1/4" pipes into individual mufflers* and 2 1/4" pipes to the rear of the truck.

Option 2...2 1/4" Y-pipe into a single 2 1/2" exhaust, into a 2 1/2" in/2 1/2" out muffler*, then a single 2 1/2" tailpipe.

Option 3...2 1/4" down pipes from the engine to a dual 2 1/4" in/single 2 1/2" out muffler*. This is a common system that Ford has used on full size trucks and the 2nd generation Explorers with the 5.0 V8 (I have 2). I personally like this option best for performance improvement for a mostly stock engine as well as the best sound. The mufflers tend to be a little more expensive.

Option 4...is very simalar to option one, but with the addition of an H-pipe or balance chamber before the mufflers. This helps with performance and balances the pressures in each exhaust bank.

(mufflers*) this is where you decide on budget, sound and material. I try to stay away from the obnoxious cackle of cheap glasspacks. A high quality straight through or chambered muffler will give the best performance and sound. Try to find YouTube clips of different mufflers with stock engines. Muffler placement affects sound as well as bends and length of the tailpipes.

Tailpipes...remember, there is a reason auto makers didn't exit the tailpipes straight out the back. As the truck goes down the road, a vacuum is formed behind the tailgait and in the open bed. The exhaust gasses get trapped in these areas when the pipes exit strait out. The gasses can get pulled into the cab through open door windows and rear sliders...not good. It's best for the tailpipes to be side exit. If you must go straight out the back, a simple bed cover eliminates the danger.

If you want to hear an Explorer 5.0 with a dual in/single out chambered muffler, PM me and I can get a sound clip to you. It picked up fuel mileage, power and sounds great. Dual 2 1/4" in and single 2 1/2" out with no added tip. A tip could also hurt or help the sound.