New Y-pipe and cat for the old girl

[FighterOfTheFoo]

TBI was around until 1999 on these trucks too. Yours a Mexican model by chance?

As far as I could find online (which may not be entirely correct) it has been in the US its entire life. Did they keep using the TBI's in Mexico?

 

[L31MaxExpress]

As far as I could find online (which may not be entirely correct) it has been in the US its entire life. Did they keep using the TBI's in Mexico?

Yes and they also offered the 250 inline six too in both TBI and multi point injection. The 99-07 trucks still had the old Vortec 350 in many of them down there too.

 

[someotherguy]

1995 454 would have had the newer model P4 PCM regardless if it were an automatic or manual. GM needed it to run the linear EGR valve. 4.3L was also equipped the same way. Only the SBC/Manual transmissions from 93-95 used the old C3 style ECM.

Good info. Regardless that 1995 3500HD was 1 wire o2 from factory. Also the weird setup where the original pancake pellet style cat was behind the muffler instead of ahead of it. And yes, absolutely was the linear EGR on that 454. I recall it, plus double-checked the pics from that truck.

As far as I could find online (which may not be entirely correct) it has been in the US its entire life. Did they keep using the TBI's in Mexico?

Yes but with Vortec-style accessory drive.

The 10th digit of your VIN is the final word on what year model your truck is. If it's an S, your truck is a 1995. T, 1996. 1995 was the final official year for TBI engines in U.S. market GMT400's, with the very rare exception of some fleet/government type models. Always exceptions when you say stuff like that.

Richard

 

[L31MaxExpress]

Good info. Regardless that 1995 3500HD was 1 wire o2 from factory. Also the weird setup where the original pancake pellet style cat was behind the muffler instead of ahead of it. And yes, absolutely was the linear EGR on that 454. I recall it, plus double-checked the pics from that truck.


Yes but with Vortec-style accessory drive.

The 10th digit of your VIN is the final word on what year model your truck is. If it's an S, your truck is a 1995. T, 1996. 1995 was the final official year for TBI engines in U.S. market GMT400's, with the very rare exception of some fleet/government type models. Always exceptions when you say stuff like that.

Richard

The ones I have seen personally had Vortec heads, a 2" bore TBI unit and matching manifold setup for the large footprint IAC casting of the later 2" bore TBI unit without EGR on them. This exact same manifold in fact although this was a marine unit. I have also seen this manifold on the 1996 fold forward hood G-van looking P-series chassis with a governed TBI like a 366/427 used. Those also had the pellet box cat after the muffler on a 350. I changed the intake gaskets on one, manifold was a beast to yank out of a van being cast-iron.

Even the mid 2000s Mexican L31s in the GMT800s had an EGR block off on them.

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[99xcss4]

The ones I have seen personally had Vortec heads, a 2" bore TBI unit and matching manifold setup for the large footprint IAC casting of the later 2" bore TBI unit without EGR on them. This exact same manifold in fact although this was a marine unit. I have also seen this manifold on the 1996 fold forward hood G-van looking P-series chassis with a governed TBI like a 366/427 used. Those also had the pellet box cat after the muffler on a 350. I changed the intake gaskets on one, manifold was a beast to yank out of a van being cast-iron.

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hens teeth unobtainium?

 

[L31MaxExpress]

hens teeth unobtainium?

They are out there, but likely hard to find. Probably easier to find in the used marine market. GM power rating for the TBI Vortec, 235 hp @ 4,000 rpm and 325 tq @ 2,800. 4,000 rpm would be the maximum governed engine speed as well for those. Typically they have a 4 speed mechanically shifted AT545 behind them with a drum style parking brake. The AT545 typically uses the throttle governor to help it make a WOT upshift, the governor snaps shut creating high vacuum and the modulator lets it upshift, governor comes off and it stays in the next gear. Remove the governor and the shifting gets very goofy, ask me how I know that one.

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This was an earlier 93-95 350 engine with the governed TBI option. These run the 30 psi fuel system if anyone ever runs across one and no mention of that fact anywhere. Saw a shop put a typical 15 psi TBI pump in one and it would barely run. They claimed it had "other" issues with the TBI system, which I tracked back to them installing the wrong pump into it. These manifolds are small block manifolds with 2" throttle openings from GM as well.

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[Tomcat71]

The ones I have seen personally had Vortec heads, a 2" bore TBI unit and matching manifold setup for the large footprint IAC casting of the later 2" bore TBI unit without EGR on them. This exact same manifold in fact although this was a marine unit. I have also seen this manifold on the 1996 fold forward hood G-van looking P-series chassis with a governed TBI like a 366/427 used. Those also had the pellet box cat after the muffler on a 350. I changed the intake gaskets on one, manifold was a beast to yank out of a van being cast-iron.

Even the mid 2000s Mexican L31s in the GMT800s had an EGR block off on them.

You must be registered for see images attach

LOL I was just looking at a marine Vortec tbi manifold on fleabay .lol and here it is.