4.0 block interchange

[stx4.0]

I am curious if anyone knows why a 95 model 4.0 block will not work in a 94 or earlier model?It says in the 4.0 tech/rebuild section of this site that they will not.The only difference I see listed on the 95 is a couple extra holes added to each side of the block.I dont see why that would keep it from being used in an earlier model.Same with the heads.They say stay with same year heads but only difference I see is combustion chamber.I think compression stayed the same or close and exhaust and intake mounts stayed the same?

 

[Ranger44]

The blocks themselves are totally interchangable.

The heads on the other hand aren't. Not entirely anyhow. People have ran the older heads(90/93TM) with the newer management(95-97) without too many problems. But if you were to run the 95TM (used 95-97) with the older mangement (90-94) you'll have some bad pinging issues, unless you run 92/93 octane fuel. Which wouldn't be that bad of thing if you were looking for a performance build. As it basically increases compression. Maybe adding 10hp.

 

[stx4.0]

I figured the blocks should interchange.I dont know why they have that written in the 4.0 rebuild section that they are not interchangeable.I had heard before the heads would increase compression,especially the use of the 98tm heads.Those heads have small exhaust ports though so I dont know what gains would be had from the use of them.I know a smaller exhaust port will get you an increase in torque but I think on an engine with air/fuel modifications it might hurt overall performance and power.Guess you could always port them a little if necessary.Then as you say you would have to deal with the right engine management sytem.It would be great to have someone custom burn a chip and reprogram everything but its hard to find someone to do that for the earlier(97 on back)4 liters.I bought a jet chip for mine right after i bought it.Total waste of money,no gains in performance or fuel mileage,it was like it wasnt even in there so a reprogram is probably the way to go.

 

[wahlstrom1]

They changed the engine mounts as the trucks got newer. They only added holes, but never took any away, so in theory you could throw a 00' OHV 4.0L in a 90, but not a 94- into a 95+ truck etc. Thats how it was explained to me, which is why a dyno'd 200+ RWHP 4.0 thats fairly local isn't in my truck yet.

-andrew

 

[F150hybred]

Now, correct me if I'm wrong here... but the 95 and newer (95tm) engine came with dished piston to allow for the smaller chamber of the heads... so if someone was to use a complete engine from a 95 with say 94 or older computer, sensors etc... it should work... correct?

 

[stx4.0]

You would probably have to use the 95 computer with a 95 shortblock however we are talking just the bare block itself.If I was to use a 95 block with my 94 internals then my 94 ECM would be fine.

 

[Snoranger]

im currently installing a 91 block into my 95 explorer. there is only one hole in the older block that lines up with the newer mount. you have to make adapter plates to install the mounts. to go from a 95 block to a 91-94 mount, you just bolt it on.

 

[Ranger44]

Now, correct me if I'm wrong here... but the 95 and newer (95tm) engine came with dished piston to allow for the smaller chamber of the heads... so if someone was to use a complete engine from a 95 with say 94 or older computer, sensors etc... it should work... correct?

The early 4.0's also had the deep dish pistons.

 

[AllanD]

The late ('95-up) 4.0's have the same mechanical C/R as the earlier
(90-94) 4.0's and since the combustion chambers are smaller
on the later heads it can be presumed that the dish in the later pistons is larger.

My "spare engine" which is in the early stages of assembly is a low
mile 2000 engine and it's got the later pistons and is getting a set of new heads.

I'd only use the late heads on an early block if I lived in colorado or wyoming.

The extra compression compensates for the altitude.


AD

 

[dorman68]

Here are some notes from a hollander salvage interchange index.

EXPLORER 95 (6-245, 4.0L, VIN X)
EXPLORER 96 6-245 (4.0L, VIN X)
MAZDA B-4000 95-96 (6-245, 4.0L, VIN X)
RANGER 95-96 6-245 (4.0L, VIN X)


Does not include engine wiring harness.
Change induction & electrical systems as necessary.
Upper intake manifolds '91-92 have no EGR holes & '93-94 are available with or without EGR holes.
Switch oil pans as necessary. Pan changes in 1994.
Exhaust manifolds must be switched '91-92 & 93-94.

 

[F150hybred]

So then I was rite, an engine from say a 95 or newer (not ohc) would work so long as it was used complete except for swapping the sensors etc. Cool!