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https://www.youtube.com/watch?v=dnKY-wm6G2A
There are times I wish I had just left the exhaust like it was.
But the hedders anddual exhaust sue makes my favorite chore, replacing the rear main a lot easier.
No worries man, Thank you
I've got a pile of them stock style mufflers...If they didnt plug up the exhaust so much I would run them on my 77. I like the way they sound.
About a year ago I decided to improve my exhaust a bit. I added a big magnaflow, it has a 3-1/2" single exit piped to the side behind the rear tires. The inlet is a dual 2-1/2" plumbed to stock 460 with truck manifolds. It is nice and quiet but sounds good to me. Plus I feel it has more power throughout the range. It had a drone under load at about 1800 rpm cruise in top gear. I watched a video by david vizard about helmholtz resonators and did the measurements and calculations to build one on my setup. I either have the calculations wrong or need to tune the length because I still have the drone but it is noticeably quieter. Interestingly what sold me on this resonator idea is they are putting them on trucks with the new 7.3 gas engine. The idea is you find the resonance (drone) frequency, I used a free phone app. Then calculate the length equivalent to half that wavelength and it cancels it out. The problem is it is dependent on temperature and other things.
Factory cast iron intake, new 650 and single exhaust.
I sometimes wonder just how much more power I actually gained from the Performer intake, hedders and dual exhaust.
Driving the truck the only difference that I could feel with the new intake manifold was at the bottomof 3rd gear on a 2nd to 3rd shift.
And I wish these weren't such lousy road tires because they would eat my current Ironman M/Ts for a snack.
About a year ago I decided to improve my exhaust a bit. I added a big magnaflow, it has a 3-1/2" single exit piped to the side behind the rear tires. The inlet is a dual 2-1/2" plumbed to stock 460 with truck manifolds. It is nice and quiet but sounds good to me. Plus I feel it has more power throughout the range. It had a drone under load at about 1800 rpm cruise in top gear. I watched a video by david vizard about helmholtz resonators and did the measurements and calculations to build one on my setup. I either have the calculations wrong or need to tune the length because I still have the drone but it is noticeably quieter. Interestingly what sold me on this resonator idea is they are putting them on trucks with the new 7.3 gas engine. The idea is you find the resonance (drone) frequency, I used a free phone app. Then calculate the length equivalent to half that wavelength and it cancels it out. The problem is it is dependent on temperature and other things.
My friend that did my exhaust made this 2.25" from the collectors to 3".
I did a single 3" on my 1972 F-250 390 4V.
I wanted the exhuast to look stock so he used a 3" mandrel bent tail pipe.
I thought it looked and sounded great.
390, 1966 Ford 390 GT S intake and factory Holley, Hi-Tech Racing Reactor camshft, Hedmen Hedders and a 3" exhasut with a Flowmaster muffler.
I sold that truck in 2009 with less than 42,000 original miles on it.
I needed the money for inventory for a new business.
I really regret selling this one.
