86 LG4 y-pipe or upgrade options
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Car: 1986 Z28
Engine: 5.0 LG4
Transmission: 5-speed
86 LG4 y-pipe or upgrade options
I accidentally posted this question in the Wanted section, so hopefully it makes sense here. New guy!!
First time 3rd gen owner here! I just got my 86 Z28 LG4 5-speed yesterday. It has a cobbled up mess of an exhaust system that I need to take care of right away. They y-pipe was hacked and welded into a really terrible full dual exhaust that is about 3" from the ground. I don't have any need to upgrade for power, etc., just to get it back to stock or close to stock. I have other cars I can race, this one is just for cruising. If I had a stock LG4 y-pipe I would start there and work my way back with stock 2-1/4" exhaust. I don't, so should I put a wanted ad for one, or is it easier to swap manifolds and get the larger HO stock y-pipe that is available and run the larger exhaust? My goal is to be back on the road as quickly as possible with as close to stock setup as possible. Thanks for any opinions!!
First time 3rd gen owner here! I just got my 86 Z28 LG4 5-speed yesterday. It has a cobbled up mess of an exhaust system that I need to take care of right away. They y-pipe was hacked and welded into a really terrible full dual exhaust that is about 3" from the ground. I don't have any need to upgrade for power, etc., just to get it back to stock or close to stock. I have other cars I can race, this one is just for cruising. If I had a stock LG4 y-pipe I would start there and work my way back with stock 2-1/4" exhaust. I don't, so should I put a wanted ad for one, or is it easier to swap manifolds and get the larger HO stock y-pipe that is available and run the larger exhaust? My goal is to be back on the road as quickly as possible with as close to stock setup as possible. Thanks for any opinions!!
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Car: 1991 R7U Z28 1LE
Engine: LB9
Transmission: T5
Axle/Gears: G92 3.42 Truetrac
Re: 86 LG4 y-pipe or upgrade options
My last 1986 LG4 I took Sofa's advice and I threw away the complete stock system and bought a used large stock Y-pipe from Frank's Pontiac Parts from a LB9 or L98 with a 3 inch outlet. I added a 3 inch stock replacement catalytic converter (Catco or MagnaFlow) hung by the stock hanger. Then I added a Flowmaster American Thunder 3 inch system. Beautiful sound I liked. Then I threw away the 305 and built a 355 L98. Shazam! Wonderful!
The one I have now is a LB9 305 that came with a horrible cobbled up Y-pipe. This time I tried the MagnaFlow stainless steel Y-pipe with 3 inch outlet. Got a 3 inch MagnaFlow stock cat and finished it off with the MagnaFlow stainless cat-back system. I like the sound and much quieter interior noise level.
There a some higher flow cats out there but I went with the easy stock fit.
The one I have now is a LB9 305 that came with a horrible cobbled up Y-pipe. This time I tried the MagnaFlow stainless steel Y-pipe with 3 inch outlet. Got a 3 inch MagnaFlow stock cat and finished it off with the MagnaFlow stainless cat-back system. I like the sound and much quieter interior noise level.
There a some higher flow cats out there but I went with the easy stock fit.
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Robert2020 (08-17-2022)
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Re: 86 LG4 y-pipe or upgrade options
I have a pair of L98 manifolds and a 3” Magnaflow Y-pipe in PHX if you’re interested. Knocked .80 off of my LU5 with a catback.
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Re: 86 LG4 y-pipe or upgrade options
Last edited by 1983LU5TA; 10-17-2022 at 10:02 PM.
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Car: 1989 IROC-Z 305 LB9 AT Convertible
Engine: LB9 305
Transmission: AT
Re: 86 LG4 y-pipe or upgrade options
Oh! A Third Gen site? I’ve only been here 10+years! I’ve got my eye on a 92000 mile corvette L98. Complete, for my 89 IROC Z VERT. Mike
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Re: 86 LG4 y-pipe or upgrade options
10+ years? I’ve been here for over 22 years under various usernames/accounts. Not sure what that has to do with anything. You asked about Corvette manifolds, which I never mentioned in my reply. I answered your question. They don’t fit.
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