Anyone running 70 Series Flowmasters? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

jmking9 · 11-12-2013, 11:05 PM

Looking to see if anyone has went from 40's to the 70 series.
First a little info on my current setup: 355c.i. RPM aluminum heads, 284 Comp XE cam, full length headers, 2.5" exhaust (no x or h pipe) with FM 40 series dumped in front of the axle. While this setup sounds great to me, I would like to tone it down just a bit. I still want to keep it dumped in front of the axle.
Before I spend 300 bucks I wanted to see if anyone had any experience with this swap. All the videos on you tube don't demonstrate the difference in interior drone. And that is the main reason I would like to try something quieter. Thanks for any input.

**Already Gone** · 11-12-2013, 11:09 PM

subscribed

**davischevy** · 11-12-2013, 11:43 PM

I picked my 71 GMC Longhorn from the muffler shop this afternoon. It is a big block with stock manifolds. I had Flowmaster 40's with the exhaust in front of the wheels. Was a little annoying. I had the exhaust run out in the stock location, and retained the Flowmasters. It is quieter in the cab and sounds perfect.

jmking9 · 11-13-2013, 12:48 AM

Quote:

Originally Posted by davischevy

I picked my 71 GMC Longhorn from the muffler shop this afternoon. It is a big block with stock manifolds. I had Flowmaster 40's with the exhaust in front of the wheels. Was a little annoying. I had the exhaust run out in the stock location, and retained the Flowmasters. It is quieter in the cab and sounds perfect.

I agree, adding tailpipes would cut down the drone. I thought about trying that, but I just dont like the look of them. No offense to those that do, but "turndowns" have always been my personal preference.

1968k10blue · 11-13-2013, 01:34 PM

Have them dump right behind the bumper, so you can't see the pipes, and you get that extra distance from the cab

joesgreen67 · 11-13-2013, 04:22 PM

I'm running Delta 50's dumping out behind the rear tires.

They're sort of quiet, but could still be a little quieter.

I use to have 40's. I just couldn't stand that drone.

jmking9 · 11-17-2013, 10:43 AM

Well, I went ahead and ordered the 70's. If I can figure out how to post videos, I'll post some comparison videos. I'm anxious to hear them compared to the 40's.

BugzC10 · 11-17-2013, 11:07 AM

Subscribed...I also have 40s dumped just before rear axle. Like to hear what yours will should like with the 70s

11-12-2013, 11:05 PM	#1
jmking9 Registered User Join Date: Sep 2006 Location: Riverton KS Posts: 832	Anyone running 70 Series Flowmasters? Looking to see if anyone has went from 40's to the 70 series. First a little info on my current setup: 355c.i. RPM aluminum heads, 284 Comp XE cam, full length headers, 2.5" exhaust (no x or h pipe) with FM 40 series dumped in front of the axle. While this setup sounds great to me, I would like to tone it down just a bit. I still want to keep it dumped in front of the axle. Before I spend 300 bucks I wanted to see if anyone had any experience with this swap. All the videos on you tube don't demonstrate the difference in interior drone. And that is the main reason I would like to try something quieter. Thanks for any input. __________________ 1970 SWB Build

11-12-2013, 11:09 PM	#2
Already Gone 70+ ( Old Skool Club ) Join Date: Nov 2003 Location: Saskatoon, Saskatchewan ,Canada Posts: 9,143	Re: Anyone running 70 Series Flowmasters? subscribed __________________ 1972 C10 Custom/Deluxe 613 Highlander 406/700R4 1999 White Tahoe LS 4x2 with Z56 Police Package 1992 K1500 GMC Suburban Members I have personally met: MusicMan70 - HeavyD - ChewyChevy67 - StingRay -71SWB4x4 - 67 Burb - DeadheadNM - too much stuff - bc65 - das601 " Circumsatances Do Not Change Responsibility " " The Sky is not the Limit, Your Mind is." Marilyn Monroe .. RIP Charlie Watts 1941 - 2021

11-12-2013, 11:43 PM	#3
davischevy Senior Member Join Date: Sep 2008 Location: Harrison, Arkansas Posts: 9,860	Re: Anyone running 70 Series Flowmasters? I picked my 71 GMC Longhorn from the muffler shop this afternoon. It is a big block with stock manifolds. I had Flowmaster 40's with the exhaust in front of the wheels. Was a little annoying. I had the exhaust run out in the stock location, and retained the Flowmasters. It is quieter in the cab and sounds perfect.

11-13-2013, 01:34 PM	#5
1968k10blue Registered User Join Date: Aug 2013 Location: Mahtomedi, Minnesota Posts: 335	Re: Anyone running 70 Series Flowmasters? Have them dump right behind the bumper, so you can't see the pipes, and you get that extra distance from the cab __________________ Austin 2005 GMC Sierra 1500 4X4 4.8l V8 (Wrecked) 2003 Chevy 1500 standard cab short bed 4x4 w/ 5.3l

11-13-2013, 04:22 PM	#6
joesgreen67 Registered User Join Date: May 2009 Location: Goldsboro NC Posts: 151	Re: Anyone running 70 Series Flowmasters? I'm running Delta 50's dumping out behind the rear tires. They're sort of quiet, but could still be a little quieter. I use to have 40's. I just couldn't stand that drone.

11-17-2013, 10:43 AM	#7
jmking9 Registered User Join Date: Sep 2006 Location: Riverton KS Posts: 832	Re: Anyone running 70 Series Flowmasters? Well, I went ahead and ordered the 70's. If I can figure out how to post videos, I'll post some comparison videos. I'm anxious to hear them compared to the 40's. __________________ 1970 SWB Build

11-17-2013, 11:07 AM	#8
BugzC10 Registered User Join Date: Oct 2012 Location: Rose Hill Kansas Posts: 1,351	Re: Anyone running 70 Series Flowmasters? Subscribed...I also have 40s dumped just before rear axle. Like to hear what yours will should like with the 70s __________________ 1970 C10 Short Stepper with 71/72 front clip.

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