Engine swap questions

[87silveradok20]

I have yet to see a thread exactly like this so I figured I’d start it. So this winter I am going to swap the motor in my truck. The truck is an 87 k20. I’ve narrowed down what I want down to 3 options. 1) crate 350 or 383 with aftermarket efi, 2) 6.0 and 4l80, 3) Cummins with dodge overdrive trans. The truck is just a driver and will occasionally pull a trailer but not a huge one. If I go with a gas motor I will probably get 350-400 hp out of the motor. If I go Cummins I probably will leave it relatively stock and just turn it up some. I want it to have good road manners and I don’t have a huge budget to do all this. So what would you do and why.


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[Honky Kong jr]

Cummins is probably cheaper then a good crate engine and FI. And well it's a Cummins is why....but I'd mate it to a 4L80 not a Dodge transmission.

 

[87silveradok20]

Cummins is probably cheaper then a good crate engine and FI. And well it's a Cummins is why....but I'd mate it to a 4L80 not a Dodge transmission.

Do you think a 4l80 would hold up to the low end torque?


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[yevgenievich]

Do you think a 4l80 would hold up to the low end torque?


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program to disable shift to 4th gear at wot and it should be fine with a relatively stock cummins.

 

[Honky Kong jr]

And with the Cummins a little fuel plate massaging is all you'd need for a cruiser light tow rig. And what Viktor said

 

[87silveradok20]

And with the Cummins a little fuel plate massaging is all you'd need for a cruiser light tow rig. And what Viktor said

I actually would probably go with a ve pump unless I got a good deal in a p pump motor but yeah same concept essentially.


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[87silveradok20]

program to disable shift to 4th gear at wot and it should be fine with a relatively stock cummins.

If I wanted to build the transmission down the road would it be cheaper to build a 4l80 or a non electrical dodge trans to hold the same power.


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[Honky Kong jr]

Dodge doesn't have a very good track record with automatic transmissions. Can they be built up sure but with a 4L80 you get the proven dependability of a TH400 with OD.

 

[87silveradok20]

Dodge doesn't have a very good track record with automatic transmissions. Can they be built up sure but with a 4L80 you get the proven dependability of a TH400 with OD.

Trust me I know plenty of people who have had trouble with dodge transmissions. I have heard tho that they can be made very reliable. I’m not trying to diss the 4l80 I just wanna make sure I can get a good idea of what’s the best option for me in my situation. I also understand if I asked which trans is better on a dodge page they would all say the dodge trans.


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[4WDKC]

I must be living in the wrong place, 200k mile 6bts are 2-3k here without a transmission. Based on how little you will be towing it depends on the cost of engines in your area. For example for me
3k 6bt +transmission + tcase(?)+ odds and ends
2k crate/rebuild + 1k efi + odds and ends
$800 6.0+ 500 4l80e+ tcase(?)+ odds and ends

I left off the things that would be common between all 3 liek exhaust work, fuel lines, etc. I am usually not a LS swap fan but when coming from a carb setup its hard to beat the budget junkyard swap.

 

[4WDKC]

Dodge doesn't have a very good track record with automatic transmissions. Can they be built up sure but with a 4L80 you get the proven dependability of a TH400 with OD.

NV4500 problem solved?

 

[Honky Kong jr]

NV4500 problem solved?

There is that too. Or dare I say Allison....

 

[87silveradok20]

I must be living in the wrong place, 200k mile 6bts are 2-3k here without a transmission. Based on how little you will be towing it depends on the cost of engines in your area. For example for me
3k 6bt +transmission + tcase(?)+ odds and ends
2k crate/rebuild + 1k efi + odds and ends
$800 6.0+ 500 4l80e+ tcase(?)+ odds and ends

I left off the things that would be common between all 3 liek exhaust work, fuel lines, etc. I am usually not a LS swap fan but when coming from a carb setup its hard to beat the budget junkyard swap.

You think the way I do. Let me modify your list a little so it’s closer to what things are like in my area and how I would do it (maybe).

1st gen Cummins (full truck) 5k+ odds and ends- selling rest of truck
6.0/4l80 $1500+ transfer case adapter
Crate $3500+ $1000 efi

My prices are probably a little higher than what they actually would be. But they should be close.


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[87silveradok20]

NV4500 problem solved?

I like that idea but I want an auto in this truck.


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[87silveradok20]

There is that too. Or dare I say Allison....

Slow down now. I don’t have that much to throw in for this project. Maybe some day tho...


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