Flowmaster Exhaust System

Discussion in '1965 - 1973 Classic Mustangs -General/Talk-' started by Randy'65, Mar 31, 2014.

  1. Thinking about getting a flowmaster exhaust system, from collectors back. I'm wondering what kind of 'fabrication' I can expect to do to get the kit to match up to headers. I have an old set of Blackjack headers (I think Hedman bought them at one time or another) that I installed in the late '80's, not sure what I will go back with after I get a new engine. Will it be close enough that I can piece together some pipe sections so I can drive it somewhere to get welded up? Or will it require heavy modifying of the h-pipe?

    Second question, is the 2-1/2" system adequate for a moderately built 331?
  2. cant answer the fab question, thats best left for an exhaust shop if you ask me unless you have all the equipment for it.
    However, a warmed over 331? running dual 2.5" pipes all the way out should be ok. im running 2.5"-40 series-2.25" on one of my 200's, and it works awesome. That setup will do good
  3. 2.5" pipes will be fine. But are you ready for the drone from the Flow masters? It sounded mean at full throttle. But I could not stand cruising that way and quieted it down with some super turbo mufflers.
  4. Yeah....Flowmasters are a catch 22. Sound absolutely awesome when you're romping on it, but will drive you insane with interior resonance noise any other time.

    I had the Mac Flowpath mufflers on a previous Fox body a few years back and they were very similar to the Flowmasters....and they were LOUD!!!

    I've got a set of the Pypes Race Pro mufflers on my 331 now and damn if they don't sound awesome. Quiet and subtle around town...with almost "zero" drone to them....probably as drone free as you're going to get from an aftermarket muffler, but absolutely SINISTER when you stand on it. So much so, that I'm considering welding a set of cats into my mid pipe just to take some of the bark out of them.....but then I'm also getting old.
  5. I installed a Dyna Max system on my 69 351 Clevland with FPA headers. The exhaust fit was perfect. Just had to have the pipes stretched to fit the FPA header collectors. And remove two inches from each pipe for a perfect bolt up. I was impressed.
  6. I put the 40 series on my 35 Ford pick up ,i wanted 50 series but they were to long to fit. the 40s really sound good but they are loud .I had 50 series on my 66 Ford truck and loved them .A friend of mine gave me the headers for the 66 ,don't know what brand they were but they were new and the fit perfectly .Both trucks have 347 302 s