Choosing a Powertrain

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vicnation

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Location
NC
First Name
Tristan
Truck Year
1976
Truck Model
k10
Engine Size
350
I have a 76 K10 shortbed fleetside that I am building (restoration with small modifications) for resale. It has a 2" lift and will run 32" tires. I am looking for a good combination of engine, transmission, transfer case, and gear ratio.

The original 350 engine will either be rebuilt or replaced. I would like to have an engine with higher torque at lower RPMs. For numbers, I'm looking at between 420 and 500 ft. lbs. at the lower RPMs. My options as I see them are rebuild the original 350, buy a crate 383, buy a crate big block, find a used big block and go through it, or do an LS swap.

To rebuild my 350, I've had a quote for about $1200 for the machine work. Then I would put aluminum heads, intake (already have headers), torque cam, FiTech fuel injection and plumbing, serpentine setup and aftermarket AC. Without the AC, it would cost around $5K for the parts and work. I have not pulled the pan yet to determine if it is a 4-bolt or 2-bolt. It does have 67K original miles.

I can get a 383 crate engine with decent specs for $5k-$6K with fuel injection.

It looks like a big block crate engine like a 454 HO would cost between $7500-$8500 with everything I will need. Will the 1/2 ton frame support a big block? Did Chevrolet put a 454 in a 1/2 ton shortbed?

It is difficult to find a decent used big block in my area that would be suitable for a rebuild. At first glance, it would cost me approximately $6-$7K to get one and rebuild it with the necessary parts.

If I did an LS swap, I would prefer an LQ9 but I haven't been able to accurately estimate the costs.

I would prefer to replace my original TH350 with a 4 speed automatic. My options as I see them are a 700R4, 4L60e and 4L80e. I will have to modify driveshafts, linkage, throttle cable, etc. I can get a core 700R4 for $350 and it would cost about $1100 to build it. At that point, I still don't know if it will handle the torque. The 4L60e would cost about $600 for a core. Then I would have to have it built and get a control module and harness. Like the 700R4, I don't know if this could handle the torque I will get from the engine. The 4l80e should handle the torque but I would need a harness, module, rebuild costs, etc.

I have an NP203 installed with a part time kit. NP205 is preferred but difficult to locate locally. It would cost about $1300 online. Other options include the NP208 or NP241. I would also need the proper adapter.

Going to a 4-speed, I will probably put 4.10 gears in the differentials. I have a Dana 44 front and a 12-bolt rear. I plan to put some type of locker (limited slip) in the rear.

It's a lot to consider but I am looking for a drivetrain combination that will have the best return on investment. Any advice would be appreciated.

Thanks...
 

Honky Kong jr

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Denver,PA
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J-me
Truck Year
87
Truck Model
V10
Engine Size
Lil BB 407
Bigblock and a Th400 or 4L80
 

vicnation

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Location
NC
First Name
Tristan
Truck Year
1976
Truck Model
k10
Engine Size
350
Can the frame of a 1/2 ton shortbed support the weight and torque of a big block?
 

Honky Kong jr

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Denver,PA
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J-me
Truck Year
87
Truck Model
V10
Engine Size
Lil BB 407
Can the frame of a 1/2 ton shortbed support the weight and torque of a big block?
1/2 ton and 3/4 ton share the same frame. I have a big block in my V10(1/2 to 4x4)
 

yevgenievich

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Viktor
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sad
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very sad
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less sad
3/4 frame is thicker, but I believe it is for towing reasons
 

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