3" tailpipes...? A few questions... - Lateral-g Forums

boynton6spd · #1 03-03-2011, 07:22 AM

I have a 3" exhaust on my 67 Impala. (502 BBC)
I currently have a x pipe and 2 3" flowmasters w/Dumps before the rear axle...
I would like to run 3" tailpipes out the rear, but I'm having trouble finding them...
Would Chevelle tialpipes work...I've seen them online in 3" but no look looking for Impala pipes...
Would 2.5" tailpipes hurt performance?

wmhjr · #2 03-03-2011, 07:47 AM

Ah, the age old debate. Heres my opinion.

2 1/2" tailpipes are extremely unlikely to hurt you as the exhaust gasses have cooled quite a bit by then.

Chevelle tailpipes probably won't fit. You can either find a shop locally that can mandrel bend 3" or you could order some bent pieces online and tig weld them to fit.

**214Chevy** · #3 03-03-2011, 09:23 AM

Quote:

Originally Posted by wmhjr

2 1/2" tailpipes are extremely unlikely to hurt you as the exhaust gasses have cooled quite a bit by then......You can either find a shop locally that can mandrel bend 3" or you could order some bent pieces online and tig weld them to fit.

Exactly the two choices I was going to say. 2 1/2 more than likey won't hurt or have them made at a custom exhaust shop.

wmhjr · #4 03-03-2011, 09:37 AM

I'll also say that if it's a normal 502, you're making tons of torque and probably in the low 500s hp. With that kind of torque curve and power output, I can't see any way that 3" would help - yet it will certainly be more difficult to install and route. If there were an advantage to 3" for you, it would be in the upper rpm ranges, where the 502 typically isn't run all that much. On top of that, if you're retaining the dumps, you've pretty much eliminated tailpipes in all out track use anyway.

I used 3" all the way, however I'm at the 600hp level, and there were some pre-formed segments available from Ram Air Restorations available. Even so, I have a slight fitment issue around the drivers side rear axle. They are TIGHT. And we did some cutting and tig welding to better customize the fitment too.

If I were you I'd stick with 2 1/2". Also, if you're really wanting 3", make sure it's mandrel bent. If not, with every bend you're eliminating any advantage of the larger diamter and making it actually worse. You may find that local shops often can't do 3", and many that can are not able to mandrel bend that diameter.

boynton6spd · #5 03-03-2011, 10:01 AM

Thanks....alot of knowledge and help on th board!!!
I think I'll go with 2.5 mandrel bent...!

wmhjr · #6 03-03-2011, 10:34 AM

Good luck, and stick some pics up of your progress!

chr2002ca · #7 03-03-2011, 05:44 PM

Yep, since you're running an X pipe, 2.5" tail pipes should not restrict flow at all with your engine. Definitely go mandrel bent though on the tail pipes. I'm running that exact setup(3" exhaust, X-pipe, 3" mufflers, 2.5" tail pipes) with my ZZ454. It's so much easier dealing with the 2.5" tail pipes in terms of fitment and suspension travel.