How bad will a Vortec 4.3L be in an FJ40?

[Lil'John]

Title basically states it.

I'm in drivetrain planning for my 75 FJ40 that has no drivetrain but has stock motor/trans mounts on the frame.

In the past, I ran a 5.0L TBI with SM465 to push 4.11 gears and 35s. It worked for when it was installed. It was an L03 out of a Camaro rated at ~170hp and ~255ft-lbs I wouldn't pay a cent to get the same engine

I've got a 4.3L sitting in a retired 2000 S10 that I'm considering. The only reason I'm considering it is the fact it is free. It is rated at ~180hp and ~250ft-lbs. It works reasonable in the S10.

I'm considering going 4.3L + stock NV3500 tranny to Blackbox to split case. In theory, with the engine fully shifted forward, the NV3550 shifter comes out in the stock FJ40 shift location. The Blackbox takes the place of an adapter and should be good to go for rear axle driveshaft.

Any flaws in this line of thinking beyond there being better new drivetrains I could spend money on?

EDIT
I guess I should post intended use.

Mostly "daily" when there is no snow or rain(only have a bikini top right now). Mid level wheeling. Home base will be Wentworth Springs outside of Georgetown so "backroads" to Rubicon and Hell Hole. Virtually no freeway.

 

[Wilson]

I’ve had a few trucks with 4.3’s and was never disappointed in what they did. As long as someone uses a transmission that came behind a 4.3, and minds the axle gearing; it should be fine. Toss a th400 behind it, or insist on a 4.xx axle ratio and it may suck.

 

[Lil'John]

I'm looking at either a 33" or 35" tire. Nothing more. Gearing will be either 4.30 or 5.29(non-FJ40 axle being installed)... choice of gearing depends upon what I do for other two rigs

I'm considering the NV3500 because it is free(ie in truck) and potentially put the shifter at stock location while allowing me to push the engine super far forward(basically V8 location if looked at by the fan)

The NV3500 has ZERO adapters that I've been able to find Except for a 5 bolt to 6 bolt adapter. I could do that and then do the Blackbox.

An auto is off the table completely. Not my cup of tea.

I don't need an over drive. I rarely get out of 3rd gear when driving Wentworth into Georgetown I don't recall the last time I've been on a freeway

 

[PAToyota]

The FJ40 was 125~135hp stock and they also put the 4.3 full-size pickups and vans. I know that isn't comparable to today's market, but the 4.3 shouldn't be shabby in comparison to the stock FJ40. Keeping the NV3500 makes sense to me, but I'm a manual-type guy.

 

[u2slow]

180hp sounds low for a vortec. The S-blazer of that era was 195hp IIRC, and the earlier CPI actually got a 200hp rating for a couple years. If it is 180hp, it may be as simple as a ECM swap or reflash to 195hp.

My TH400 experience suggests it would be an unresponsive slug behind the V6. OTOH, with a manual trans it will feel like it has some punch.

The NV3500 (or NV4500) from a fullsize will be 6-bolt already, and have a 32-spline output instead.

 

[Lil'John]

180hp sounds low for a vortec. The S-blazer of that era was 195hp IIRC, and the earlier CPI actually got a 200hp rating for a couple years. If it is 180hp, it may be as simple as a ECM swap or reflash to 195hp.

My TH400 experience suggests it would be an unresponsive slug behind the V6. OTOH, with a manual trans it will feel like it has some punch.

The NV3500 (or NV4500) from a fullsize will be 6-bolt already, and have a 32-spline output instead.

I just double checked... it was 190hp(2000 4wd with W vin) 200hp was limited to 1994 or 2003/4.

There are two issues with the NV3500 or NV4500 out of a fullsize: I don't have either and the shifter ends up forward of the S10 version. Plus I really don't want to pay upwards of $2k for an NV4500.

Here is fullsize NV3500:

Here is S10 NV3500:

If I were thinking of buying a transmission, I would do a 2wd SM465 then an aluminum top to push the shifter back. But, the last time I looked for one, it was ~$500 for the trans and ~$300 for the top

 

[u2slow]

The sequential-efi vortec didn't start until 96+ (obd2), and its the one to have regardless of the earlier hp ratings.

It been so long since I played with chevy nv3500's I forgot the shifter location.

To get the manual trans you want nowadays, its usually cheaper to buy a whole roachy truck with one.

 

[PAToyota]

I misread NV3550 as NV3500.

 

[Lil'John]

It been so long since I played with chevy nv3500's I forgot the shifter location.

To get the manual trans you want nowadays, its usually cheaper to buy a whole roachy truck with one.

My first thought was to swap to the "big" nv3500. It took a bunch of time to find pictures of both. I also thought about swapping the tailshaft/output shaft. Then found the weird setup.

It is also looking like Advance is discontinuing a large part of their LC adapters I'll be calling Monday to see if that is the case.

I misread NV3550 as NV3500.

When I posted originally, I had typed nv3550 but I thought I had changed my OP to nv3500 before a reply. I have a similar issue transmission dyslexia

 

[IowaOffRoad]

I dunno, my kooky idea is to put a slant 6 in mine for the same reasoning as yours pretty much. I have all the parts to do it so why not? Can’t be worse than a stock engine.

 

[Lil'John]

I dunno, my kooky idea is to put a slant 6 in mine for the same reasoning as yours pretty much. I have all the parts to do it so why not? Can’t be worse than a stock engine.

Back when I originally bought the 75, I had a fresh rebuilt 2F in it with 6-1 header and Malory Unilite distributor. It ran pretty damn nice except for the fact that it wasn't fuel injected and Calif wouldn't let me convert at the time

I won't do a 2F now since I don't have one and people think a buildable core is worth $1k+

 

[lpukas2]

My buddy ran a 4.3 in a CJ7 with the stock axles with 35" tires. He used to drive back and forth from PHX to TUS and got really good mileage. Lots of power but he never did dumb shit with it.

 

[Wulf]

I think you'll be happy, the 4.3L should not leave you wanting power but also won't be too much to have to always worry about the drivetrain

 

[Lil'John]

A concern I have is if I don't push the engine forward, I'll end up with a light "quirky" weight distribution biased to the rear.

I know that the FJ40 will end up being roughly the same weight as the S10 after all the mods(drivetrain, axles, suspension, etc). Both actually start at same curb weight between 3000 to 3500 depending upon source. Engine goes from ~750lbs to ~375lbs. I'm not sure on weight gain from trans and transfercase but I'm guessing about 50lbs to 100lbs. Axles might be a big gain. I'll be doing hybrid Tunda 10.5 and Dana 60s... I probably gain full engine weight savings back.

MPG is probably about as far down my list of worries. I'm a boring fawk and the drive will be mountain roads where there won't be any real cruising. When I currently drive the s10, I rarely got out of 3rd gear for about 10 miles to get into town.

 

[Elvis-n-texas]

My 83 has a 08 4.3. AA to W56 adaptor with Marlin Doubled cases /4.7/2.23.
I'm on true 37's and 4.88's and the rig will run over 100.
4.3 torque and the low gears makes it creep well with needing an auto.