Are they the same?
Y pipe for '88 5.0 V-8 and '88 5,7 V-8?
Thanks.

 

yes they are ezactly the same. The 305 and 350 are really identical. the only real difference is 3.75" pistion in the 305 and 4.00" in the 350.

 

Different.

From TransamGTA350:

There were only 2 different manifolds for the V8's throughout the years, but they were different depending on what motor and gearing package they came on. Here is the breakdown.

2" outlet manifolds with single 2 1/4" y-pipe
82-87 305 LG4 (VIN H)
88-92 305 L03 (VIN E)
82-83 305 Crossfire
90-92 305 LB9 w/o G92 axle (VIN F)

2 1/4" outlet manifolds with single 3" y-pipe
83-86 305 L69 (VIN G)
85-89 305 LB9 (VIN F)
88 350 L98 (VIN 8)
89 350 L98 w/o G92 axle (VIN 8)

2 1/4" outlet manifolds with dual 2 1/4" cats
89 350 L98 w/G92 axle (VIN 8)
90-92 350 L98 (VIN 8)
89 305 LB9 w/G92 Axle (VIN F)
90-92 305 LB9 w/G92 (Vin F)

The manifolds from the single 3" cat and the dual 2.25" cats are interchangeable. On the passenger side manifold, some will have the heat riser butterfly valve, some will have a spacer, and some will just have a donut gasket. You most likely have the wrong manifold for your application. If you have the larger manifolds, then it may be worth it to get the larger y-pipe for some more performance.

JamesC

 

I can get a new Y-pipe for the 5,0 V-8 overhere, but it doesn't say if it will fit the 5,7 V-8 that I own....
They look the same, but it doesn't fit according to the post directly above?

 

Check post #7 in the link below for a comparison pic between an LG4 (2" outlet / 2 1/4" Y) and an L69 and/or an L98 (2 1/4" outlet / 3" Y). A 305 could scarcely breathe with the LG4 version little lone a 350.

https://www.thirdgen.org/forums/exha...-question.html

JamesC

 

Thanks for the info.