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1981 Forest service Scrambler.

masscj2a said:
Does anyone recognizthe frame mounted engine mounts ? Are they all the same or did they use different ones for different engines?

And yes I agree, the 4bt is heavy. The cummins 2.8 would be my choice as well, if within my price range. The 307 is already built, with block hugger headers. The 700R4 is the manual OD and already adapted to the Dana 300 with low max gears. That is the easiest choice to make and the 307 is slightly built to around 225 HP. I'd like to put on EFI on it, but thats all it needs. Always liked the 307, even though I know its a bastard child in the family.
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I as always completely forget about the Chevy 307. Those weren't around very long. Whenever people talk about having a 307 my mind always jumps to the Olds 307. But anyway, if you already have a good healthy one in your garage I would use it. And if it fails it would be easy to swap in another SBC.

Just throwing this out there, but the 700R4s 4th gear is only a .7 ratio. So with 33s and 3.73 gears you would only be at 1800rpm at 70mph which would be unusable. It would be constantly downshifting if you tried using 4th. That constant gear hunting builds up a lot of heat and would kill that trans in a very short amount of time. Leaving it in 3rd gear and using it as a 3 speed would be fine. That would put you at 2600 rpm at 70mph. If you actually want 4th gear I would go straight to 4.56s. Those would put you at 2200 rpm at 70 with your 33s which would have great drivability and the best chance at decent MPGs
 
Ron84cj said:
I as always completely forget about the Chevy 307. Those weren't around very long. Whenever people talk about having a 307 my mind always jumps to the Olds 307. But anyway, if you already have a good healthy one in your garage I would use it. And if it fails it would be easy to swap in another SBC.

Just throwing this out there, but the 700R4s 4th gear is only a .7 ratio. So with 33s and 3.73 gears you would only be at 1800rpm at 70mph which would be unusable. It would be constantly downshifting if you tried using 4th. That constant gear hunting builds up a lot of heat and would kill that trans in a very short amount of time. Leaving it in 3rd gear and using it as a 3 speed would be fine. That would put you at 2600 rpm at 70mph. If you actually want 4th gear I would go straight to 4.56s. Those would put you at 2200 rpm at 70 with your 33s which would have great drivability and the best chance at decent MPGs
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I ran 4.10 gears, 33" tires, TBI 350, and a 700R4 for a few years with no issues :shrug:

The overdrive is deep, like the much maligned LJ auto, but it was never constantly shifting 4-3-4-3. Most of the time I would manually shift from 4 to 3 and back when passing etc. Maybe the 350's torque was a better match than the 307 :shrug:
 
masscj2a said:
What is this rubber pad on passenger front disc? And this is the first time I've seen what I think is a steering stabilizer mount on a spring mount.
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Stock steering stabilizer mount for sure.
As far as the block on front disc I like the idea of maybe some sort of wiper to clear debris from the rotor but no evidence of one on drivers side? Definitely home brewed in the Forestry shop
 
spankrjs said:
I ran 4.10 gears, 33" tires, TBI 350, and a 700R4 for a few years with no issues :shrug:

The overdrive is deep, like the much maligned LJ auto, but it was never constantly shifting 4-3-4-3. Most of the time I would manually shift from 4 to 3 and back when passing etc. Maybe the 350's torque was a better match than the 307 :shrug:
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With 4.10s you were a little over 2000 rpm at 70. That's what a lot of the 350TBI Chevy trucks were at in the late 80s early 90s which was...ok. I very firmly believe they were a little under geared. Did your Scrambler have a lockup converter in it? All of my old Chevy trucks struggled at freeway speed. The converters would constantly lock and unlock. It absolutely drove me nuts. Being in a much lighter weight Scrambler I'm sure yours did much better. My point here was that if he was going to re gear, he would be much happier going to the 4.56 to get a couple hundred extra rpms out of it which does make a very big difference. Especially being a 307. I have a very hard time believing the 307 makes as much low rpm torque as the 350. Just my opinion here.
 
Ron84cj said:
With 4.10s you were a little over 2000 rpm at 70. That's what a lot of the 350TBI Chevy trucks were at in the late 80s early 90s which was...ok. I very firmly believe they were a little under geared. Did your Scrambler have a lockup converter in it? All of my old Chevy trucks struggled at freeway speed. The converters would constantly lock and unlock. It absolutely drove me nuts. Being in a much lighter weight Scrambler I'm sure yours did much better. My point here was that if he was going to re gear, he would be much happier going to the 4.56 to get a couple hundred extra rpms out of it which does make a very big difference. Especially being a 307. I have a very hard time believing the 307 makes as much low rpm torque as the 350. Just my opinion here.
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No worries :thumbsup:

Yes, mine had the lock up torque convertor. I had my TC controlled by the ECM. Mine would never unlock in 4th gear. I think the ECM controls vary by vehicle, mine came out of a Caprice Classic.

I thought about controlling the lock up with a toggle switch, but in the end left it alone.

I do agree, 4.56 would probably be better with 33's, especially if you have to regear anyway.

Same with the LJ automatic. 31's and 4.10's are OK, if I had ever went to 33's it would have had 4.88's swapped in before the tires ordered!!!
 
I would agree with what was stated above. I have 4.88s on 35” tires. The .7 OD in the 700r4 is deep. I think 4.88s were ideal with the 33” tires I ran prior to the 35s. My 4.3 is making less power than the others though. That said most folks (myself included) would prefer to err on the side of being too numerically high. For most people a 40+ year old Jeep just doesn’t need to go faster than 65 mph.

I used all sorts of gear calculators. I wanted to ensure that I could run highway speeds in either 3rd or 4th if the 4.3 couldn’t hold speed on a hill.
 
OK, so it's been a while. I've had 3 jeep projects going at the same time and the scrambler was not one. I'm trying to get a few done to sell and pay off my mortgage and gets funds for a couple of other projects including the scrambler.


But guess what I have collected for parts last year. Yeh I'm going to blow this all up now, because I just couldn't help myself. I picked up a newly built 401 and a low miles NV3550 and another dana 300. I bought a 100% rust free cj7 out of Colorado with 401, rebuilt 727 and 300 with low max kit. So I'm going to use the 401 in the 8 with the nv3550. Then I picked up a 360 out of a 88 wagoner that had been Rebuilt 10k ago.
So watcha think about a fuel injected 401? And my tranny choice.
 
I forgot to say that the 360 will be going into the cj7 for a flip maybe with T176 and Dana 300.
 
masscj2a said:
OK, so it's been a while. I've had 3 jeep projects going at the same time and the scrambler was not one. I'm trying to get a few done to sell and pay off my mortgage and gets funds for a couple of other projects including the scrambler.


But guess what I have collected for parts last year. Yeh I'm going to blow this all up now, because I just couldn't help myself. I picked up a newly built 401 and a low miles NV3550 and another dana 300. I bought a 100% rust free cj7 out of Colorado with 401, rebuilt 727 and 300 with low max kit. So I'm going to use the 401 in the 8 with the nv3550. Then I picked up a 360 out of a 88 wagoner that had been Rebuilt 10k ago.
So watcha think about a fuel injected 401? And my tranny choice.
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I don't think efi on the 401 is a bad idea. Any chance of improving MPGs is always good. And with AMC V8s you will need all the help you can get. I had a 304 in one of my scramblers and it was TERRIBLE on gas, the 360 in my other Scrambler was also TERRIBLE on gas (absolutely nothing I did with it helped either). I was originally building a 401 for my blue Scrambler and then it kind of hit me...I actually want to drive the thing daily and having an engine that only gets single digits for gas mileage just wasn't going to cut it for me. So I sold that and built a 258 with MPI. That motor blew up so I gave up on anything AMC engine related and bought a Chevy 5.3L. I now have close to 300hp and average 17 to 18 MPGs and have hit 20 mpg multiple times. Not bad for 3.5" lift on 32s with a wind sail of a top. I'm just not a fan of the old AMC V8s anymore. They were great engines for their day, and that day was 50 years ago. The cylinder head technology is ancient and anything aftermarket for them is super expensive. If I were you I would sell the 401 (which you will make good money on) and put it towards something more modern. It's not like the 360 or 401 was original to CJs anyways. Plus AMC Jeeps ran a lot of Chevy parts from the factory so it wouldn't be blasphemy. Just my opinion.

If you do stick with the AMC V8 then I guess the Holley sniper would likely be the easiest way to get EFI on it. There are a few people here that have done that, hopefully they will chime in.
 
He is right AMC is old technology, but our Jeeps are old and mostly not daily drivers so MPG does not matter that much. I like your sticking with the a
AMC 401. My Scrambler has a FI350. My last one had a 401. My 7 has a sniper 360:which I enjoy driving
Some people like the 3550. i sell TJ parts and it seems like a lot off the 3550 have synchro problems.
 
Belizeit said:
What is the mpg on that rascal ?
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Last time I checked, it was "IDGAF"

:rotfl:

Literally no clue because I can't fill the tank full to get any kind of measure to use. I'm using the aux tank in the rear as the main and the design is so bad that it overflows out the filler neck going around any right turn (the clear fuel overflow corrosion on the side under the filler shows this).

I truly don't give a rip and it's a huge part of why I went EFI. I know that the engine is doing the best it can (given my timing/dizzy setup, of course) and that's all I need. I could try to tweak the EFI settings to maximize things if I did have the ability to calculate MPG, but it's got WAY more power than I ever really use and drives (mostly) great, so I just let the settings ride.
 
mwqpd11 said:
He is right AMC is old technology, but our Jeeps are old and mostly not daily drivers so MPG does not matter that much. I like your sticking with the a
AMC 401. My Scrambler has a FI350. My last one had a 401. My 7 has a sniper 360:which I enjoy driving
Some people like the 3550. i sell TJ parts and it seems like a lot off the 3550 have synchro problems.
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I'm hoping it's a good tranny. Had very little use. They put in an auto for their daughter because dad couldn't get her to figure out the 3550. I have the new 727, but the scrambler came as a 3 pedal and kinda like it that way. I have a couple of t176's, but I wanted a little newer shift. Hopefully it works out.

Fuel mileage I could get a rats butt care about. 🤪 If it burns a tank a day and I have a Batman's jokers grim while doing so, I'll be happy.
 
Well I was just curious. I like to check both mine just about every time I fill up. That actually let me know something was going on one time. Not much I can change on mine to make it better
 
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