A little confused on the SOA

[Tire_fryin89]

So not new to off-roading, owned and built 6 jeeps and a few trucks etc, but this is my first FSJ. 1964 J20 Thriftside. My confusion comes from the front suspension setup. The axle is already under the spring but it doesn’t appear to have any lift to it. Was there a factory SOA setup or were the older trucks setup this way already? I’ve searched but haven’t been able to find much info.

[tgreese]

Hi - welcome from Boston.

Thriftsides are cool trucks. The higher GVWR trucks could have had the long bed Thriftside, which is quite unusual.

Why do you call it a J20? There was no J20 until 1974. In '64, it could be either J-100, J-200 or J-300 designation, depending on the GVWR. Look here http://www.ifsja.org/tech/figures/index.html

Regarding the spring over, yes I recall that the earliest trucks were spring over. Look at Gr 11 - L3 in the '62-73 parts book here https://oljeep.com/edge_parts_man.html There is also a service manual available from all the usual Jeep retailers. I don't have it but I expect it might have some hints about equipment and configuration.

What do you want to do with this truck? The Kaiser trucks have a lot of issues, mostly due to antiquated or obsolete design. How is your truck equipped? Are you sure it's really a '64? A '64 would only have the OHC 230 from the factory, and while it's an interesting and great-looking engine, it's hard to love as a daily driver. Part are expensive and scarce, and it takes a lot of effort to maintain them in good running order. They were hated in the day, and likely contributed to Kaiser disposing of the Jeep marque to AMC. These pre-65 units have a lot of issues.

[Yeller]

Yes the pre 73 trucks were spring over from the factory. That is why the springs are on the outside of the frame and the turning radius is quite limited by the closed knuckle front axle, and spring location, that is if it is original.

[Tire_fryin89]

Hi - welcome from Boston.

Thriftsides are cool trucks. The higher GVWR trucks could have had the long bed Thriftside, which is quite unusual.

Why do you call it a J20? There was no J20 until 1974. In '64, it could be either J-100, J-200 or J-300 designation, depending on the GVWR. Look here http://www.ifsja.org/tech/figures/index.html

Regarding the spring over, yes I recall that the earliest trucks were spring over. Look at Gr 11 - L3 in the '62-73 parts book here https://oljeep.com/edge_parts_man.html There is also a service manual available from all the usual Jeep retailers. I don't have it but I expect it might have some hints about equipment and configuration.

What do you want to do with this truck? The Kaiser trucks have a lot of issues, mostly due to antiquated or obsolete design. How is your truck equipped? Are you sure it's really a '64? A '64 would only have the OHC 230 from the factory, and while it's an interesting and great-looking engine, it's hard to love as a daily driver. Part are expensive and scarce, and it takes a lot of effort to maintain them in good running order. They were hated in the day, and likely contributed to Kaiser disposing of the Jeep marque to AMC. These pre-65 units have a lot of issues.

Yes it’s a 64. And yeah J200 and I know that from running the number on the tag. It’s all original with the 230 and 4 speed. I dropped a turbo LS and T56 and Holley EFI in my 67 camaro so the straight 6 will be gone soon enough that’s not an issue. My confusion was with the front suspension setup. I searched far and wide for an early short bed thrift on purpose and I planned on different axles. I just didn’t know if I needed to get ready to fab up a new suspension setup or what. It’s going to be a driver/work truck. Going to run 31s and probably drop in a 5.3 or a late model hemi. Is there a go to leaf spring and axle that people like to run for these? 4 link and coils? I’m definitely not spending $1800 on 4 leaf springs for it though.

[will e]

Yes the pre 73 trucks were spring over from the factory. That is why the springs are on the outside of the frame and the turning radius is quite limited by the closed knuckle front axle, and spring location, that is if it is original.

All these years and I didn't know this. Of course I have never owned one that old but it's cool to learn something new.

[Yeller]

Sounds like it’s going to be a cool truck. Your tire size choice will fit fine with no lift. I ran 33x12.50’s with no lift, they just barely fit.

As for suspension it’s pretty archaic. I did a 3 link with Early Bronco coils on the front and 63” Chevy springs in the rear. It rides and drives amazing.

There is not much out there for the stud mount springs. The ride ok until you find a road in poor condition then it’s not very good lol. If your accustomed to old cars and newer trucks you’ll be disappointed without some serious suspension mods. The outboard mounted springs along with the closed knuckle front seriously hamper turning radius, enough that parking lots can be frustrating.

[Stuka]

Yes it’s a 64. And yeah J200 and I know that from running the number on the tag. It’s all original with the 230 and 4 speed. I dropped a turbo LS and T56 and Holley EFI in my 67 camaro so the straight 6 will be gone soon enough that’s not an issue. My confusion was with the front suspension setup. I searched far and wide for an early short bed thrift on purpose and I planned on different axles. I just didn’t know if I needed to get ready to fab up a new suspension setup or what. It’s going to be a driver/work truck. Going to run 31s and probably drop in a 5.3 or a late model hemi. Is there a go to leaf spring and axle that people like to run for these? 4 link and coils? I’m definitely not spending $1800 on 4 leaf springs for it though.

The most common thing people do for 64-73 trucks is to move the springs under the frame like 74+ J-Trucks used. This makes swapping in later J-Truck axles a bolt in (ish) and with roughly the same amount of lift. Or if you are wanting more lift, a spring over with the under frame springs gives about 7" of lift.

If you are wanting stock-ish height, you can leave the stock spring setup. But it does hurt turning radius and the only company that makes springs for them is Hell Creek.

What are your ultimate plans? iTs worth noting the older trucks don't really make good "trucks" unless you essentially swap out everything. Especially a 64 as it doesn't have a saginaw steering setup, it has the old bell crank system. They make fine cruisers to restore, but not a good candidate for offroad. You said you were going to swap the axles, so I won't get into the timebomb that is the stock tapered shaft axles if a V8 gets put in front of them.

[fulsizjeep]

All these years and I didn't know this. Of course I have never owned one that old but it's cool to learn something new.

SHAZAM! It's a good day when I can learn something new about FSJs. In 8 months, I have yet to see another one on the road in Sarasota. I had to drive 100 miles to pick up another NP208 for my GW and that's because the seller met me halfway.

[tgreese]

If it's a 4-speed, it's a T-98 which is the predecessor to the T-18. The T98 is a fine transmission but has limited parts interchangeability with the newer and prevalent T-18, and little other support. Seems a shame to take a manual transmission truck and change it to automatic - seems like lots of owners want to go the other way, which is more difficult. And as time goes on and automatics got better, the manual transmission trucks became scarce compared to automatics. There are some 5 and 6 speed manuals that you could adapt to these popular modern engines. I'd probably go with one of the LS engines; I hear the modern Hemis have oil starvation problems if operated at low speed for a long time.

The engine compartment was designed for the inline six, and in later trucks with the V8 the engine was moved forward to clear the firewall, heater and brake booster. Clearance for a V8 may be an issue unless you follow Jeep's example. These V8 trucks used a manual transmission with a very long bell housing or adapter and very long input shaft, to keep the transmission shifter in the same location in the passenger cabin. Available 5 and 6 speeds are pretty long compared to the original manual transmissions, and might fit well in this application.

[will e]

All these years and I didn't know this. Of course I have never owned one that old but it's cool to learn something new.

SHAZAM! It's a good day when I can learn something new about FSJs. In 8 months, I have yet to see another one on the road in Sarasota. I had to drive 100 miles to pick up another NP208 for my GW and that's because the seller met me halfway.

Yeah! It's why I read threads that don't really impact me. I like to learn things. I remember one post, perhaps on this forum, talking about drill bits. Someone mentioned that the max RPM was correlated to the drill bit size. The smaller the size the more RPM's 'allowed'. It had to do with the amount of heat caused by the additional surface area as the bits got larger.
Obviously it stuck with me.

Hope you are doing well on the other coast!