I am going to do a lot of editing to this page to what should have been done as this is the most common TBI engine upgrade these days and I wish I had used a better truck than that salvage flood truck for the project. Truly AWESOME setup and why its the number 1 engine on my recommended engines page. Bang for the buck its hard to beat. Great budget vortec TBI setup.
1. Starting off with a used Vortec motor that I am buying through a search of www.car-part.com and I found one for $600 shipped to me.
2. I am going to use a Edelbrock 2716 EPS series intake this time and I ordered it through Jegs part number 350-2716. This intake is a carbureted intake and has no provision for EGR. I will eliminate the EGR in the chip as I can easily get my vehicles through inspection without it. If you need to have the EGR valve to pass emissions then you must purchase the GMPP TBI vortec intake part number 12496821 $370 from Jegs . I also ordered a Holley TBI to square bore adapter for part number 510-17-45 and gaskets 375-1255 $20.
3. For the TBI unit, use a bored 46mm 600cfm TBI unit from either www.rvmorsemachine.com or www.tbiparts.com with 350 injectors at 18psi fuel pressure with custom chip kit.
4. The exhaust I am going to keep pretty simple. I am going to use the stock vortec manifolds that will be on the vortec motor when it arrives and couple them to the modified y pipe using the Flowmaster Y250300 collector. I do plan on changing the cat to a 3″ Thunderbolt cat $50 shipped on ebay and a Summit racing brand mandrel bent catback system Summit part number SUM-688011. Trying to keep this project cheap but I would like to pick up some sound quality and a little HP. I can always add the headers later.
5. I am going to put new rod and main bearings (summit part numbers FEM-2555CP FEM-4663M) as well as oil pump in my vortec motor as I feel its a $100 and 2 hrs well spent with the motor out of the vehicle.
The bearings did appear to have some wear but the crank looked really good. I used a stock Z28 oil pump which gave me some really nice oil pressure. Even on a hot motor the oil pump managed a good 50psi which is much better than any TBI motor that I have been in.
6. Since this was a 4.3L truck I will be doing some other modifications which I will post in here as I go.
— I changed the motors mounts to the V8 mount since the 4.3 is a reverse looking mount I knew it wasn’t going to bolt up easily. I reused the clam shell mount that was bolted to the vortec motor that I bought and got the rubber mounts for a 91 4×4 V8 truck as there are apparently 3 different mount possibilities for the V8 trucks so a few trips to the autoparts store may be necessary. I of course had to try all 3.
— The V6 radiator and shroud. Stock radiator is fine just do my recommended electric fan conversion which cuts up the shroud anyway.
7. Little extras are eating me up on this project which is typical of most projects. I have spend about $300 on odds and ends which others may or may not encounter. A lot of my issues stem from this truck being a flood vehicle and I have replaced everything electrical in the thing now.
Although, I didn’t dyno the motor. I can tell you the truck runs everybit as well as my 96 Vortec truck and since the motor is a stock vortec motor, I see no reason why this project would not dyno at its goal level since my 96 Vortec truck has the exhaust work and a larger throttle body and performance programming on it as well.
I also drove the truck to its new owner and got a solid 20mpg on the highway with the AC on with it. Not bad for a 4×4 truck. I can’t take all the credit for all the gas mileage. It does have underdrive crank pulley and 3.42 gears with 31.5″ tires (265/75R15) which is about 5% larger than the stock 30.5″ )245/75R16’s that originally came on the truck. The truck is also a 5spd manual which helps with the gas mileage. Since the NV3500 has a pretty low first gear the truck would easily burn those big tires through first gear and catch a gnarly 2nd gear patch as well.
Overall, I am very pleased with this project and feel it would make a nice upgrade for any TBI owner.