1998-2000 short block going in a 1991 ranger

[Kirby N.]

Hey guys- I got a good deal on a NOS Motorcraft rebuilt 1998-2000 OHV short block. I would like to build it for my 1991 ranger and put it in to replace the old tired 4.0 OHV. Unfortunately, I am pretty not smart about this stuff. Wondering if some of you can help me. I am not looking to make it more powerful or trick it out. I really just want a reliable good for another 300k miles engine.

I think I need different heads than I have in my current ranger- and different pushrods. Can anyone tell me which heads and pushrods would be good ones to put in?

Will everything else off my old engine bolt on? Anything else I need to buy? I am assuming ill need new gaskets and such for valve cover, oil pan, oil filter extension thingy.

 

[Kirby N.]

This article has some good information: https://www.enginebuildermag.com/2001/04/rebuilding-the-ford-4-0l-pushrod-v6/

It looks like my flywheel won't work. That is fine, I am already running a SOHC clutch, I can change to an 8 bolt flywheel.

It also says I will need to use a later dipstick because the hole is bigger- should be able to source one of those easily.

Here is the part that concerns me about using a later engine in the aerostars which are designed for the early engines:

Rebuilders should not install an engine with the 95TM heads and deep-dish pistons in a ’95 or ’96 Aerostar. All of these engines had the same compression ratio whether they came with the original heads with the open chambers or the newer ones with the heart-shaped chambers, so they would seem to be interchangeable, but the computer calibration that was used for the old-style heads with the open chambers will not work with the newer heads with the fast-burn chambers. In fact, “It will burn the engine down in a few thousand miles,” according to a Ford engineer who worked on this engine program. Ford continued to use the early heads on the ’95 and ‘96 Aerostar because they still came with the early calibration, so rebuilders must do the same.

That is a little concerning. Any thoughts on this? I am not running any catalytic converter on my engine- but it sounds like there is something off with the mixture calibrations for the earlier engine?

 

[Kirby N.]

No thoughts?

Here is a picture of the truck it is going in