Flowmaster 70's...they're big mofos!

[ak bandit]

They're 3" center in/center out. I paid $110 each. That's alot of cash for a muffler if you ask me! I called around locally and the cheapest place wanted $225 each! So I gladly ordered them from Jegs and choked down the $40 for shipping to Alaska. They weigh a little over 20lbs each. I think I'm going to end up doing what Yukon Jack did (kind of). Running 3" from the headers to the mufflers. And reducing to 2.5" after the muffler.

 

[Burt4x4]

Thoes are even bigger than the 70s I started with...I got the BigBlock II series that have 2.5" inlet/outlet...same length just not as fat as the 3".

 

[ak bandit]

Yep, these are also the Big Block II series. If you dont mind me asking, why did you get rid of them Burt?

 

[steve_kibbe]

Geese, thats a big sucker.

I love the sound of a FM though

 

[Burt4x4]

Well I wasn't gonna but when I got my rig to the exahust shop and up on the rack the owner and I were trying to figure out the best routing...he offered to test fit a set of 50sieres just to see if it made a difference...well the 50s seamed to be a bit of a better fit for me so the owner said he would swap my 70s for the 50s if I wanted so I said sure why not..I wasn't dead set on running 70s so I didn't really care eather way.

I think the 50s & 70s are very close for sound..I heard Greg72s first gen 396 w/70s and my 50s are very similar to his so.....

 

[vtblazer]

I just had the 50's pulled out and replaced them with the 70's.
A mellower sound IMO.
Got the BBII's also, same as yours, 3" in and out.

Good fit if you've got an 8ft bed.

2nd pair of flows I've bought, both 70 series for my big blocks.

 

[supersize75k5]

maybe because im still young, but I have always had 3 inch headers, pipes and 3 inch 40 series..

its always put a smile on my face, but I can remember not driving my blazer plenty of times because it was to loud for neighborhoods at night

how much more mellow are the 70's?

 

[Yukon Jack]

Dang, that's a big muffler! Let us know how they sound. Can you get a sound byte once you install them?

 

[Greg72]

Dang, that's a big muffler! Let us know how they sound. Can you get a sound byte once you install them?

Here's a "refresher" for you YJ....Apparently you never saw this post....?

OK.....Last July, I took my junk out to the middle of nowhere to a dyno shop that RJF suggested.... here are a couple clips of the "hard pulls" they did. Each vehicle went over 100MPH on the dyno......

Hearing Swampers at 100+ is scary! Everyone in the shop took a few steps back from the machine as it was making it's pull.


1st one:

'72K5 - 396BBC/Thorley TriY Headers/ Flowmaster 70-series duals / 4.10s & 38's....you can see the "Detroit Locker effect" when the throttle lifts too! (6MB)

http://www.norcalbigdawgs.net/bb03/pics/Dyno%20Day%20-%20K5%20Hard%20Pull.MPG




and this (bonus footage!)....

'72 Burb - 350SBC with cast manifolds and Walker Dynomax duals (12MB)

http://www.norcalbigdawgs.net/bb03/pics/Dyno%20Day%20-%20Suburban%20Hard%20Pull.MPG





Final results (I still can't find the dyno sheets, but there here somewhere) were that the K5 put down just over 300 Lb/ft of torque at the wheels, and the Burb (even with a smallblock!) put down 292!!! Talk about embarassing for the BBC!!!.....

Enjoy!

 

[Yukon Jack]

They both sound great!