- Location
- Grand Junction, CO
So this is going to be a bit of an experiment, the truck isn't quite what I was looking for and will require quite a bit of work to get it where I want. My goal is to have a reliable tow rig that gets good MPG, it simple to work on and has a reliable drivetrain.
The truck is older and more beat up than I'd prefer, but it had all the right drivetrain parts which was more important to me. The truck is a '95 GMC Sierra 2500 with 190k miles, it has a TBI 350, NV4500 and NP241 t-case. The rear axle is one of those funky semi-float 14 Bolt rear ends, which means 6 lug axles. I believe it's a light-duty 3/4 ton. I'm not sure what the gear ratio is, I was expecting 4.10's but according to the RPO code in the glovebox, it may have 3.73's which is surprising with the 350. I'll check the gear tag when I get a chance, but the axle ratio is a big deal for this project.
The truck needs a lot of work, it leaks oil, needs an alignment and the ABS light is on. The interior isn't cherry either, but with some cleaning I think it'll do. I would like to eventually clean up the interior, swap in leather seats from a newer GM truck, etc.
So my plan is to swap a Isuzu 4BD1T in place of the TBI 350, keeping the NV4500 transmission. I've been a fan of this engine for awhile, almost swapped one into my '97 GMC Sierra a handful of years ago. The Isuzu 4BD1T is a mechanical, direct-injection 3.9l turbo diesel that is similar to the Cummins 4BT, but a bit smaller, quieter and runs with less vibration. These came in the older Isuzu NPR box trucks with a turbo that wasn't great for performance. The 4BD1T I picked up came out of a truck that had 130k miles and was running well. The engine has a "remanufactured" tag on the block, so it was rebuilt at some point so I'm hoping it's good for some time. There are a lot of guys on 4BTSwaps.com that have swapped these into various rigs with good results. The 4BD1T also came in Land Rovers overseas, so it's a well known engine. With a better turbo, an intercooler and some tweaks of the injection pump these engines are capable of 400-450 ft/lbs and up to 25-26 MPG depending on vehicle weight, gearing, etc. I plan to run a Holset HE221W turbo, possibly a Dodge Cummins intercooler and injection pump tweaks. I'll probably leave the injectors and valve springs alone for now, just see how it does. I'll need an adapter to mate the Isuzu to the NV4500 and that'll be a pretty spendy part. Depending on when I have all the pieces, I'd like to start is this Summer.
The truck needs some body work and a paint job... but that'll come later on. For now I'll make sure the TBI 350 is reliable enough for some trips, but don't plan to put much money into it. I did notice that it turns 2,000 RPM at 70 MPH and the weak TBI 350 actually feels pretty decent... enough that it surprises me.
So here's the beater....
And the Isuzu 4BD1T engine, which many of you have seen already....
The truck is older and more beat up than I'd prefer, but it had all the right drivetrain parts which was more important to me. The truck is a '95 GMC Sierra 2500 with 190k miles, it has a TBI 350, NV4500 and NP241 t-case. The rear axle is one of those funky semi-float 14 Bolt rear ends, which means 6 lug axles. I believe it's a light-duty 3/4 ton. I'm not sure what the gear ratio is, I was expecting 4.10's but according to the RPO code in the glovebox, it may have 3.73's which is surprising with the 350. I'll check the gear tag when I get a chance, but the axle ratio is a big deal for this project.
The truck needs a lot of work, it leaks oil, needs an alignment and the ABS light is on. The interior isn't cherry either, but with some cleaning I think it'll do. I would like to eventually clean up the interior, swap in leather seats from a newer GM truck, etc.
So my plan is to swap a Isuzu 4BD1T in place of the TBI 350, keeping the NV4500 transmission. I've been a fan of this engine for awhile, almost swapped one into my '97 GMC Sierra a handful of years ago. The Isuzu 4BD1T is a mechanical, direct-injection 3.9l turbo diesel that is similar to the Cummins 4BT, but a bit smaller, quieter and runs with less vibration. These came in the older Isuzu NPR box trucks with a turbo that wasn't great for performance. The 4BD1T I picked up came out of a truck that had 130k miles and was running well. The engine has a "remanufactured" tag on the block, so it was rebuilt at some point so I'm hoping it's good for some time. There are a lot of guys on 4BTSwaps.com that have swapped these into various rigs with good results. The 4BD1T also came in Land Rovers overseas, so it's a well known engine. With a better turbo, an intercooler and some tweaks of the injection pump these engines are capable of 400-450 ft/lbs and up to 25-26 MPG depending on vehicle weight, gearing, etc. I plan to run a Holset HE221W turbo, possibly a Dodge Cummins intercooler and injection pump tweaks. I'll probably leave the injectors and valve springs alone for now, just see how it does. I'll need an adapter to mate the Isuzu to the NV4500 and that'll be a pretty spendy part. Depending on when I have all the pieces, I'd like to start is this Summer.
The truck needs some body work and a paint job... but that'll come later on. For now I'll make sure the TBI 350 is reliable enough for some trips, but don't plan to put much money into it. I did notice that it turns 2,000 RPM at 70 MPH and the weak TBI 350 actually feels pretty decent... enough that it surprises me.
So here's the beater....
And the Isuzu 4BD1T engine, which many of you have seen already....
