89 to 91 catback interchangability
01-13-2010, 03:15 PM
#1
Member
Thread Starter
Join Date: May 2000
Location: Budd Lake NJ, USA
Posts: 206
Likes: 0
Received 14 Likes
on
3 Posts
Car: / 89 IROC /
Engine: 305 TPI
Transmission: 700R4
89 to 91 catback interchangability
I need a new muffler on my 89 305 TPI. A guy is parting out his 91 RS 305 TBI and offered to sell me his Magnaflow catback. Does anyone know off-hand before I go digging if this catback is interchangable with my 89?
01-13-2010, 04:13 PM
#2
Supreme Member
Join Date: Jun 2006
Location: West-Central
Posts: 2,199
Likes: 0
Received 1 Like
on
1 Post
Car: 91 Trans am
Engine: built 360 TBI
Transmission: built 700r4
Axle/Gears: 10bolt/3.23
Re: 89 to 91 catback interchangability
The 87-92 TBI cars came with 2 1/4 in pipe ewerywere, smallest diameter for TPI cars was 2.5in. TPI intermediate pipe should be 2 3/4 in.
01-13-2010, 06:06 PM
#3
Moderator
iTrader: (14)
Join Date: Mar 2000
Location: Littleton, CO USA
Posts: 43,169
Likes: 0
Received 35 Likes
on
34 Posts
Car: 82 Berlinetta/57 Bel Air
Engine: LS1/LQ4
Transmission: 4L60E/4L80E
Axle/Gears: 12B-3.73/9"-3.89
Not in '91-'92. Single cat 305 TPI got the small exhaust, same as TBI.
But, in the OP's case, it might be a downgrade. If the I-pipe and muffler inlet are 3", then the only issue will be the connection to the cat.
Only way to know is to check out exactly what he's got.
But, in the OP's case, it might be a downgrade. If the I-pipe and muffler inlet are 3", then the only issue will be the connection to the cat.
Only way to know is to check out exactly what he's got.
01-13-2010, 06:44 PM
#4
Supreme Member
Join Date: Jun 2006
Location: West-Central
Posts: 2,199
Likes: 0
Received 1 Like
on
1 Post
Car: 91 Trans am
Engine: built 360 TBI
Transmission: built 700r4
Axle/Gears: 10bolt/3.23
Re: 89 to 91 catback interchangability
I never saw a 91-92 305TPI with single cat, though I have seen many but not all. They all have dual cat with aprox 2 3/4 to 3in intermediate pipe same exact as the 350TPI.
In the OP's case the intermediate pipe fitting/inlet of the 91RS muffler, will be smaller then his 89TPI intermediate pipe.
Yes definally mesure the intermediate pipe.
In the OP's case the intermediate pipe fitting/inlet of the 91RS muffler, will be smaller then his 89TPI intermediate pipe.
Yes definally mesure the intermediate pipe.
Last edited by thomas1976; 01-14-2010 at 04:56 AM. Reason: english
Thread
Thread Starter
Forum
Replies
Last Post
