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Discussion Starter · #1 ·
i have a 1991 conversion van, weighs in at 5800lbs,. it has an anaemic 350 motor in it,.it's hard on fuel and gutless,
(700 r4, /3.73's) and now won't pass the emissions test due to high HC content,
what idea's are there for a motor that will get better fuel mileage, more power etc,?/ i know nothing much about tbi motors,. i hear vortec this and vortec that, but no one seems to have done much in reality,.the motor is a flat tappet old 350,. i was thinking of upgrading to a roller motor with a better choice of camshafts etc,. i,m told that the emissions needs a 3way?? catalytic converter? do aftermarket flowmaster cats etc converters do the job?
has anyone else have experience with a truck or van like this ??
thanks
nick
 
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Discussion Starter · #2 ·
Maybe look into a TPI motor out od a Camaro or Firebird. The TPIs made great torque down low, which is good for your heavy van, and has a more advanced injection system than the TBI, which is better on gas.
 
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Discussion Starter · #4 ·
LT1 that pig!!!!
Miles ahead of a TBI(my opinion/experience only, don't start another discussion).
Programming, monitoring, support, all there.
We'll head to Fred's and scrounge everthing we need, harness, fuel lines, evap canister,fans.
Get it all set-up and running before you put it in.
Same as my '93, leave the 700R4 in place.
Custom AC lines maybe.
Just went through the emission equipement rigors with an '88 Monte. Aftermarket cats are fine.

If you do choose to stay with TBI, I may donate some now obsolete parts.
(You know the lack of success I had with TBI)
I have the roller LO5 as well. Could put the stock TBI set-up back together.
 
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Discussion Starter · #5 ·
a good idea dave (and i do have a spare lt1 complete),.. BUT... the a/c on the lt1 is down low and too wide for the van frame rails,.
any idea if the early accessory bracket will fit on the lt1?? I can't see the big van with no a/c,..
nick
 
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Discussion Starter · #6 ·
THe stock 350 TPI makes more torque down low than the stock LT1. It's teh long intake runners that do it. The wiring swap would be easier too.
 
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Discussion Starter · #7 ·
I'm likely one of the only people floating around here that likes the TBI setup. I have a LS1 car, I understand the joys and pains of MPFI/SFI, and I just like the TBI just as much.

A really simple build that some people have had great success is to just add the Vortec rockers, the LT1 cam, and to tune the ECM. The stock L05 heads work just great for something like a van. This is ultra cheap and works just great.

I have something a little more elaborate I'm finishing up now. 383 Vortec stroker, Walbro fuel pump, Dynamic EFI Embedded Lockers, Moates Ostrich and Tunerpro RT, soon to have a custom four injector TBI setup, complete wideband O2 sensor engine management, true dual exhaust with longtubes, full emissions controls, and a whole bunch of little parts I had to machine for fitment into my Fleetwood.

If I wanted to in the future, the ECM setup I am using can be reconfigured to operate a TPI or LT1 induction system with MPFI batch fire control. I'll very likely stay with the TBI system and I'm itching to try forced induction with very low boost and moderate flow for some more efficiency. Not trying to break speed records, but I'd like as good around town mileage as I can get.

Apart from the 383, this stuff is CHEAP compared to the LT1/LS1 equivalents. These days I've been putting my money into the Trans Am and the time into the Fleetwood.

Anyways - good luck!
 
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