6.5 GEP NA or 5.9 12v NA?

[Lukes_deuce]

The only thing I want to add into this brainstorming is, you cannot make a standard Cummins 12 valve a NA motor. The standard injection pump are designed to sense boost, so if you take the turbo off, the truck wont run properly and it will be a complete slug and smoke like a train. If you want a NA motor, dont get a 12 valve.

 

[erasedhammer]

The only thing I want to add into this brainstorming is, you cannot make a standard Cummins 12 valve a NA motor. The standard injection pump are designed to sense boost, so if you take the turbo off, the truck wont run properly and it will be a complete slug and smoke like a train. If you want a NA motor, dont get a 12 valve.

Thats interesting. Are we talking about the p-pump? How does it 'sense' boost?
I would want a fully mechanical engine, so converting a 24v seems harder than just starting with an already mechanical 12v.

 

[WillWagner]

The governor end of the pump has a sensing line that goes to the manifold, the manifold pressure pushes on a diaphragm which in turn moves pieces parts in the governor end to allow the pump to supply full fuel. If you delete the turbo, the engine will smoke horribly. The cylinder heads have built into the casting process, a swirl factor. Without manifold pressure, that swirl effect won't happen. Timing is designed using a turbo. The "smoke limiting" design is across the board, CAV, VE, ND and P pumps use it, it is a federal emissions thing.

I second the shoehorn fit of a B in a GM chassis. No room for a fan, electric is needed, firewall needs "trimming", plumbing for intake and exhaust are kind of a cluster and it's heavy. Seen quite a few in my days, only 1 that I would have considered a good one or something I might consider. Think about this, in stock form, the B is governed at 2500 RPM, the Chryslers had a 2700 RPM gov cut off. What does the V8 turn? What will be the road speed loss if you go from 3000 - 3600 ish to 2500 ish?

 

[erasedhammer]

The governor end of the pump has a sensing line that goes to the manifold, the manifold pressure pushes on a diaphragm which in turn moves pieces parts in the governor end to allow the pump to supply full fuel. If you delete the turbo, the engine will smoke horribly. The cylinder heads have built into the casting process, a swirl factor. Without manifold pressure, that swirl effect won't happen. Timing is designed using a turbo. The "smoke limiting" design is across the board, CAV, VE, ND and P pumps use it, it is a federal emissions thing.

I second the shoehorn fit of a B in a GM chassis. No room for a fan, electric is needed, firewall needs "trimming", plumbing for intake and exhaust are kind of a cluster and it's heavy. Seen quite a few in my days, only 1 that I would have considered a good one or something I might consider. Think about this, in stock form, the B is governed at 2500 RPM, the Chryslers had a 2700 RPM gov cut off. What does the V8 turn? What will be the road speed loss if you go from 3000 - 3600 ish to 2500 ish?

Yeah I'm tied to NA, so looks like I'll be going with a 6.5.

Funny enough I was looking around to try and turn down the redline rpm of the 6.5. I would never dream of putting a 5.9 with a th400. NV4500 all the way, so theoretically I wouldnt loose any top end speed.

 

[LT67]

I would 6.5 the truck and keep it as simple as you can, cost. Take the 800 and freshen up some components.

To neuter a 5.9 when already not impressive when stock, is a step back in the power category. Put some cash into the 5.9 in a rebuild and find a Dodge to put it in. A tired 400k motor would be better if you major it and then you can maintain for another 500k.

There was a Man here putting a 292 gas into a CUCV that was a unique and interesting choice. I know that the 292 is a wise alternative for power and economy, plus an easier option to find compatible components.

Good Luck

Where can anyone find a 292 inline 6 these days... they're about as rare as an honest politician

 

[LT67]

Yeah I'm tied to NA, so looks like I'll be going with a 6.5.

Funny enough I was looking around to try and turn down the redline rpm of the 6.5. I would never dream of putting a 5.9 with a th400. NV4500 all the way, so theoretically I wouldnt loose any top end speed.

A turbo 400 is very stout. Those things will handle a lot of power and torque, plus they're easier off road compared to a clutch. Just food for thought; it may be cheaper and easier to change carriers in the differentials and go with 4:10 or 3:73 gears. With 255 85 16 Toyo or BFG KM2, you can run 65mph at 2500 rpm.

My 86 M1008 already has 255 85 16 KM2's and the goal is to eventually switch to 4:10 gears. That way I still keep low end power and travel on the highway without getting ran over lol

 

[cucvmule]

Where can anyone find a 292 inline 6 these days... they're about as rare as an honest politician

I still see them, look at full size Chevrolet cars from the mid 60's on to 1 ton, 2 ton trucks and I seen one transplanted into a 85 S10 in a salvage yard a few months ago. Talk about tight fit, core support cut out, firewall hammered back. 292's were placed into trucks into the mid 80's. I do not say rare but they are available if you want one. Like the 300 Ford they are hard to kill.

 

[LT67]

I still see them, look at full size Chevrolet cars from the mid 60's on to 1 ton, 2 ton trucks and I seen one transplanted into a 85 S10 in a salvage yard a few months ago. Talk about tight fit, core support cut out, firewall hammered back. 292's were placed into trucks into the mid 80's. I do not say rare but they are available if you want one. Like the 300 Ford they are hard to kill.

I tried to find one along with the correct motor mounts for my 79 K20 when I was going through the rebuilding process and could not find one. I was honestly surprised... and yes those things are hard to kill.

 

[cucvmule]

At least around my neck of the woods you can still find. I can throw a rock and hit one in a 70 Chevrolet truck with 3 treed. Most that are left are abandoned on old farms out of sight. And there are 292 specific parts that need to be found also to be used where a V8 once resided, auto or stick.

 

[cucvmule]

If going the 292 route you need to find more than just the engine. You need a donor truck to get the needed parts. To make the swap easier.