Dual Exhaust
Thread Starter
Racer
Joined: Jul 1999
Posts: 273
Likes: 0
From: Murphy Texas
Dual Exhaust
I have a 77 4speed that was originally an L-82, but the engine in it now is a 68 350 (on Mor-Tec, the block number states it could be a 327 or a 350, but I'm pretty sure it's a 350).
Anyhow, I don't need to do emissions testing, so I want to install dual exhaust. I currently don't have headers, but is it worth it to install dual exhaust with stock manifolds or is it a must to have the headers first?
I'm new to working on cars and don't know much about it, but I'm having fun (I'm almost done with the front suspension rebuild :)
Thanks for the advice!
Anyhow, I don't need to do emissions testing, so I want to install dual exhaust. I currently don't have headers, but is it worth it to install dual exhaust with stock manifolds or is it a must to have the headers first?
I'm new to working on cars and don't know much about it, but I'm having fun (I'm almost done with the front suspension rebuild :)
Thanks for the advice!
Drifting
Joined: Nov 2003
Posts: 1,634
Likes: 4
From: Northern NJ
St. Jude Donor '04 & '05
Re: Dual Exhaust (USA SHARK)
Do the duals. Even with the stock manifolds it has to be less restrictive and thus more power. I read somewhere that the biggest percentage boost of HP/torque that could be made w/o semi major engine work to a stock mid to late 70's vette was to get rid of the ultra restrictive single exhaust and cat. Something like a 30-35 HP increase. And with the paultry HP figures that these things produced in stock form, this certainly couldn't hurt!
Even w/o the original engine, if you presently have the 2 into 1 into 2 exhaust w/a cat, then you will have to see a reasonable increase in power with no cat and the duals.
Good Luck!
:seeya
[Modified by ACECO, 11:53 AM 2/28/2004]
Even w/o the original engine, if you presently have the 2 into 1 into 2 exhaust w/a cat, then you will have to see a reasonable increase in power with no cat and the duals.
Good Luck!
:seeya
[Modified by ACECO, 11:53 AM 2/28/2004]
Thread Starter
Racer
Joined: Jul 1999
Posts: 273
Likes: 0
From: Murphy Texas
Re: Dual Exhaust (ACECO)
Thanks guys. I suppose if I'm going to do headers, I might as well do it all at once. Just not sure about which type of headers is best and if they are difficult to install on a manual. I've seen two types, one of which is huggers. Not sure about the difference or which I'd need. Any thoughts?
Thanks again for the advice!
Thanks again for the advice!
Le Mans Master
Joined: Jun 2003
Posts: 5,446
Likes: 2
From: Not Correctly Restored Stingray Fla.
Re: Dual Exhaust (USA SHARK)
Thanks guys. I suppose if I'm going to do headers, I might as well do it all at once. Just not sure about which type of headers is best and if they are difficult to install on a manual. I've seen two types, one of which is huggers. Not sure about the difference or which I'd need. Any thoughts?
Thanks again for the advice!
Thanks again for the advice!
Race Director
Joined: Jan 2000
Posts: 12,399
Likes: 247
From: San Jose CA
Re: Dual Exhaust (USA SHARK)
I actually didn't notice much benefit going from 2-1-2 to dual exhaust. (Running 2 cats.)
Maybe 2/10 sec faster to 60.
Switching to headers was a BIG leap(7.1 -> 6.3). But I'm sure that the two modifications worked hand in hand. IE Dual exhaust would work better with headers, headers work better with dual exhaust. My cork now (aside from the engine) are likely the cats and super turbo mufflers.
-Steve
Maybe 2/10 sec faster to 60.
Switching to headers was a BIG leap(7.1 -> 6.3). But I'm sure that the two modifications worked hand in hand. IE Dual exhaust would work better with headers, headers work better with dual exhaust. My cork now (aside from the engine) are likely the cats and super turbo mufflers.
-Steve
