I just recently bought a 1975 f100, later down the road I'm looking to replace the straight 6 in it to a diesel engine. Im just wondering what diesel engine would be the best choice with the least amount of modification and a good power to fuel efficient ratio. I would like to start using this truck as a daily driver so I need something reliable, somewhat good on fuel but enough power to get me through the woods on the weekends and have a little fun with. tell me what you guys think and if you could give me a price range.

 

There are I think three Cummins swaps that are all happening right now. Just look in this forum for them (should be in the first couple pages) and see if you're wanting to go that route.

 

Build the 300 6 you have now. They match a diesel for fuel economy, and can make respectable power. A 4bt cummins build will break the bank in comparison.

 

A 6BT will be cheaper than a 4BT swap.

 

agree with co425 keep the six build it right. swap a later 5 speed and it will get the same if not better mpgs as the diesel. also i dont think the F-100 will handle the weight of a 6bt.

 

I know a 6bt will fit, but with all the suspension upgrades it will need, would it be worth it? A 4bt is light enough that you wouldn't need to screw with suspension.

I still say build the 300 6. If my truck came with a 300 I would've kept it.

 

I think you guys are right I've decided to just rebuild the engine and beef it up I'm only 19 and never realized how much torque these l6 put out!!! Screw hp idc about going fast like i said Im just using it for a daily driver back and forth to work and around town but I would like to have a little offroad fun with it on the weekends.

So what do you guys think about beefing up the engine? any ideas?

 

You could fuel inject it, or go with a little 4bbl on there with a new intake and a header.

 

I was thinkin about aftermarket intake manifold, aftermarket carb, header, high comp pistons, and caming it out y'all know of any good name brand aftermarket camshafts

 

Quickly looking at Summit looks like they have comp, crane, Howard's and Crower. All pretty good brands imho

 

Alright sweet, appreciate it man!