Hello all,

Im new to forum and figured this might be the best place to post. I just recently bought a 1987 f250 6.9l t-19 4x4 for $500. I am the second owner and the truck is in really good shape. I was told the motor has been swapped and it has an ATS turbo kit with a hypermax intake. At WOT the truck will make 10-12 pounds of boost. Since the original owner passed away and the son had power of attorney there’s still a lot unknown about the truck. I bought the truck in Kalispell, Montana where I spent this summer and I drove it back to Western New York. Truck did awesome but at 70mph it would be at 3100 rpm which I really didn’t like. It has 4.10 gears so I figured that’s the cause of that. I’m looking to restore this truck in the past i’ve welded in new cab corners and rocker panels on my last truck. Is there anything you long time members recommend? Just looking for some advice on this old girl.

 

My notes suggest the top of your torque curve is at 1,400; so, yes, you have a gearing issue if you want to roll at modern highway speeds. If you want to pull stumps, you're all set.

I would be looking for a ZF5 tranny, for sure. And, depending on your use, maybe a re-gear. 3.55s and 3.73s were available, stock.

Got a plan for mitigating the NY salt/rust? That is one fine looking truck!

Roy

 

I’ve been looking into doing a ZF5 swap and have looked at a couple threads. Without knowing the actual mileage of the truck makes me hesitant to put a lot of money into it. Also worried about buying a junk ZF5 when my t-19 shifts great. For starters i’m definitely going to put larger tires on it like 33s that should help lower the amount of rotations per mile therefore allowing the engine to have lower rpms. For the NYS rust I plan on POR 15 the frame and possibly the underside of the body. I’m going to be doing the bodywork myself so depending on if it looks like a blind man did it i’ll cover it with some bedliner.

 

so that gives you a diameter increase of like 1.5" and your speedometer will be different by like 2 MPH .. roughly... Hmmmm

your OEM tires are 31.73 right ???

 

I believe the truck has 235s on it

 

that's what I based the calc on the OEM tires are 31.73 ish

 

Do you know what’s the biggest tire I can run stock? I’ve already a big lifted truck and don’t think that’s the route I want to go

 

33 is probably largest before you run into other issues like rubbing when turning.... others here may know more about this as I don't do lifted trucks either

 

If this is a highway truck, I don't think tire size will do it.

With a non-OD transmission, you'd really want something like 1:3.0 gears...but, going taller than 3.55 is tough. I think differentials, which are heavy enough for your truck, and carry tall gears, are really hard to come by.

But, the 4-speed, plus taller tires, plus 3.55 gears...you would be clearly better off. And, you might want the 3.55s if you end up with a ZF.

Good luck with the rust. It never rests.

Roy

 

That's a clean truck!

What are the mudflaps that are on it? Inquiring minds need to know.

 

I am not entirely sure the truck was used to pull bumper-pull trailers so its more of a brush to keep rock chips down. Not sure if im going to keep it or ditch it. I like the grandpa style tbh

 

I looked into regearing and it's really expensive. The simplest way to "regear" is to just buy a replacement axle from a donor truck that has the 3.55 and swap the whole axle, rather than have a shop regear the original axle.

 

Yeah Buddy

it's not too bad IF you can do it yerself but that will still run you at least $250 bux each if ya get new gear sets, the whole axle can be had for less than $200 bux each

But them Labor charges from a shop that Knows what they are doing ..... OUCH.... and there ain't any shops down here that I would trust with it


EDIT: an Aux OD unit wouldn't be too bad but ya can't use the OD when in 4x mode... Unless you got lucky and found an OD to go between the Tranny and T-Case and that would involve MUCH work and expense.
They make a Unit that goes between the Tranny and Bellhousing search advanced adapters
Easiest option... get rid of the 4 speed.

 

The advance adapter unit would be the best route in my opinion, sure the driveshafts will have to be reworked (same as zf swap) crossmember moved back (same as zf swap) holes in floors for the extra shifter, May require the front fuel tank to be taken out (transfer case clearance) but may not since your cab+half.

But 1500 for the unit is half the price of a gear vendors, rated close to 30k gross so you can tow with it, you can keep the t19 which shifts easier and will outlast a zf several times over, cheap to rebuild (200$parts) and anyone with a hf shop press can do it.

It's not a swap for the weak but I think you'd come out way ahead by the time it's all done.

They even make one for underdrive if top speed isn't your thing but towing power below highway speeds.

I'd love to buy one but they don't offer one with both overdrive and underdrive which is a complete bummer imo. The in front boxes are the way to go with a 4x4 and there simple enough they shouldn't ever give you any fuss.

 

Just for the Fun of it ... I guess you could stack 2 in front of a tranny and have over and underdrive, the extra sticks would be real Kewl.
and maybe end up with a 2 inch driveshaft


I don't have the money to play with such things myself, BUT I have seen similar done on an old Rat Rod Show Car... IF I come across a picture I'll post it.
I have no idea how Practical it was either.