4.0 or Jasper 2.9?? I have a dilemma

[holeshot]

Ok, the 2.9 finally made its last voyage last night. Since I bought this 90 BII a month ago, I have been driving it with a rod knocking. I knew it was only a matter of time before she let go....and last night she did. lol.

I have been toying with the idea of doing a 4.0 swap, but I dont know if I do find a donor vehicle...will the swap will be reliable? Face it, anything that is 91-93 or whatever that will just plug & play right in is already just as old as my existing 2.9 and all the wiring, etc. I want something that is going to be reliable to be a daily driver. I wouldnt feel right swapping out a 15-19 yr old drivetrain unless it is rebuilt...and that isnt cheap either.

So do I spend the $2500 on a Jasper engine and drive on, or whatever I can get for a donor...then eventually have to rebuild.

My plans are to put a 6" suspension lift and 33X12.50's. I am not gonna be doing any hardcore off roading or drag racing the thing...mainly it will be driven on the street. My question is will the Jasper 2.9 have enough ass for that setup? to drive around normally on the streets with occasional off roading??

Thanks in advance!

 

[fastpakr]

A 4.0 out of the box is a huge improvement in reliability over the 2.9. Considering that you have a '90 truck that is as simple a conversion as you could possibly have, and a used 4.0 shouldn't cost more than $500 or so, it seems like an incredibly easy decision. You can always buy a Jasper rebuild of a 4.0 down the road if you really need to. The cheapest option here also gives you the best return.

 

[BlackBII]

I would never spend $2500 on a stock replacement motor for an RBV, when they are plentiful in the junkyards and in the classifieds. Especially 4.0's in Explorers with blown A4LD's...

 

[Explosive]

I'd do the 4.0 My dads doing it to his now, and depending on how his goes, I might do it to mine. His had a 2.9 Jasper and it appears to have either blew a head gasket or cracked a head. So I'd say don't spend the cash on a jasper.

 

[Sunk]

I'm with these guys, 4.0 all the way.

 

[holeshot]

Well maybe for the time being I will just swap the 2.9 out of my 86. It runs pretty good. I just wanted to put in something that I know will be reliable and worry free.

Next week it goes into the shop for a Skyjacker 6" series II lift, 4.56 gears and a locker in the rear, and I am getting 33X12.50 MTZ's on classic II's.

How do you guys think a stock 2.9 will do with that setup. If it is a turd, then it will facilitate the 4.0 swap.

 

[fastpakr]

With those gears I don't think you'll have too many complaints.

 

[Explosive]

I'm guessing it'll be no speed demon with that setup.

 

[holeshot]

True. I dont plan on driving this on the interstate or doing a lot of hwy driving. Does anyone have 4.56's and a 2.9?? curious how streetable they are with 33's

 

[fastpakr]

Again, 4.56's and 33's will be fine with a 2.9. It's not going to be a problem. Even better down the road with a 4.0, but just fine with what you've got.

 

[trail B2]

4.0

If you could drive A 4.0 around the block you would never bother with 2.9s again it makes these cars fun to drive.But I put A used 4.0 in mine and I just was checking the water and have bubbles coming up, new head gaskets be done tomorrow.Thats what your trying to avoid but i'd do it again with A better 4.0.Also just A thought but I'm putting in my engine and tranny in first then tire size,have 33'' BFG's to put on this weekend . When this is working and i'm putting in my dana 35 i'm in A lot better place to decide my gear ratio because what works for the 2.9 is to low for the 4.0 for A DD trail application.