[ks gto (Cap)]

Stroked a 421 tri-power to 454 with a comp cam. Exhaust is an x pipe with Flow Masters and the 67 HO Exh Manifold and Flow master series 50 muffler. The only change was the stroked eng, but it made the sound terrible in the 1800 to 2300 rpm range. Before with the stock 421 the sound was a nice rumble but now in that range it has kind of a "vrrrrt" sound somewhat like the imports with perf mufflers. Gotta lose that! What to do? Like the sound of Flowmaster.

[RicksGTO]

have you checked your hangers to make sure the pipes are still solidly mounted with good rubber isolators and that there isn't any metal to metal contact between the pipes and floors/frame front to back?

[ks gto (Cap)]

yep-all that is good.

[bonneville Joe]

Its the X pipe. I had the same thing happen when I tried one on a '66 2dr bonneville I had. Car had a nice deep tone then I put the X on it ( and that was the only change I made ) and it sounded like a honda when it shifted. If you have to use a crossover use an H pipe. I had an H on my 78 T/A and it made it sound just like a 5.0 mustang, when I took it off I had that nice pontiac rumble.

[ks gto (Cap)]

bonneville Joe- I called Flowmaster tech this morning. They told me the same thing. Before, as stock, there was not enough difference to notice. Increasing the cu in and hp by stroking it made the difference. I wondered a bit about their answer, but you have confirmed what they told me. Thanks muchly. Cap

[ClassJ]

I had a similar experience with magnaflow's. No crossover. Essentially I was told the engine was flowing "too much air" for the the mufflers to dampen the sound at WOT. I guess that can't be a bad thing right????

I threw on some dynomax super turbos (aka, replace every few years) mufflers and the thing sounds great. Can't seem to find any other muffler I like as much. If only they made them in 304 SS.

[misaac]

Dynomax makes stainless steel UltraFlows. This link should go to the UltraFlow spec page in their catalog.

http://www.dynomax.com/ecat/pdfs/ultrafloss.pdf

[ks gto (Cap)]

Just to post an update--Retained the x pipe and temorarily tried Goerloch Xceloraters (sp?) with band clamps, based on what a friend recomended. Still that awful import sound between 1900-2100 rpm.
Then I went back to the 50 series Flowmasters, but took out the x-pipe and installed the H pipe by Flowmaster. Got the exact sound I wanted! I realize the Flowmaster's don't flow as well, but mine is a street car and has the sound I prefer. Just wanted to put a finish on the post. Thanks all, for the input. Cap

[axle]

Originally Posted by bonneville Joe

Its the X pipe. I had the same thing happen when I tried one on a '66 2dr bonneville I had. Car had a nice deep tone then I put the X on it ( and that was the only change I made ) and it sounded like a honda when it shifted. If you have to use a crossover use an H pipe. I had an H on my 78 T/A and it made it sound just like a 5.0 mustang, when I took it off I had that nice pontiac rumble.

Leave it to Joe for the answer

[bonneville Joe]

LOL. Damn those X pipes!!! hahaha

I'm not against the H pipe, honestly and yes I'm going to say this, it made the car too loud. It made the whole car resonate. With the H off it had that knarly rumble. Love it.. I might consider putting an H on a car with less compression to make it a little louder but my W72 car is nasty enough the way it is..

[gto65lvr]

I have a pair of dougs, ram air x pipe, 3.5inch oval and spin techs and I love love love it I was not sure how if I was going to like how it sounded due to sound clips but oh boy it makes a statement and really I cannot say I have a drone from them just the noise LOL.

The tones are fantastic with my build

[bonneville Joe]

I would like to hear it. Spintech's are a totally different monster than a Flowmaster. I had one on a '88 T/A and it was QUIET.....

[gto65lvr]

If I get off my butt and get a video card for my recorder, got the cam but no card hows that working out?

Then I will have vid of the car and sounds posted. I have been so busy have not had a chance to get to a store to get one.

[hectore3]

BUt is'nt the X pipe worth more power?

[Bandit79403Dave]

Do you know what "line" of Spintech's they were: Sportsmans, Pro-streets, super Prostreets?

Thanks,
Dave

[gto65lvr]

actually there was only one choice because they are 3.5 inch I guess they are sportsman ultras

I have had super turbo dynomax, flowmaster 40 series, glass packs and something else but with this set up they sound pretty sweet it is amazing when you are really rapping it