I've been able to resolve the temp high/fuel low spikes by cleaning the electrical connection at the fuel sender on top of the fuel tank. Advice from an old Mudd thread. It worked temporarily. When I changed the sender/float with new OEM; the problem went away and never returned.
The gasket is supposed to stick out the back. You're good.
To install it incorrectly a tech would need to cut off the extra in front so the water pump would mount. I've seen it done by a young newbie who didn't want to pull the head after torquing it down.
Define 'difficult to drive'. I've driven 60's for years with crap bushings creaking and knocking when I turn but it was across town and not at highway speeds. Drive it home off interstate and fix it later.
If the bushings are truly falling out, you might be able to knock the rest out with a...
Are all the heating coolant lines connected correctly? Water pump small lines to heater and return?
1/4" of heat gasket sticking out the back, none in the front? Marlin is good but it is possible to flip the head gasket upside down and the coolant holes are different front to back.
My HJ-61 OEM 15" wheels had a back spacing of 2 3/8". The only modern wheels you will likely find are custom steelies. You could run 1 1/2" wheel spacers. Not ideal but it worked for me for a couple of years until I swapped out to a FJ-80 rear axle and did the Tundra brake mod, which allowed...
The HJ's have a small amp just for the subwoofer placed next to the subwoofer. It's not large enough to do much beyond the 5.5 factory speaker. Wiring to it is 24V and line voltage inputs (not speaker level inputs).
The OEM wiring for the head unit is interlaced with the wiring to a factory...
The pivot bolt ears and tensioning bolt ear were cast as if it was supposed to attach to the left side of the engine instead of the right next to the battery. '87 FJ-60, 2F desmogged. Not an OEM casting. All the internals were the same. Forward and aft dimensions aligned. Came without the...
Years ago I received a mirror image clocked alternator as a rebuild from a LAPS. I was stranded and had to use it. My solution was to disassemble both units and move the bearings, bridge, and armature from the rebuild into the old case. Worked for years.
I've had the kickdown cable stick just as you described. It caught and released a few times then eventually stuck in 1st gear until I replaced the cable. For my 62 the problem was caused by corrosion (salty roads) where the cable enters the transmission. Numerous attempts to lube the cable...
I've set up 3 dual battery systems in 60's and run them long enough to find what didn't work.
150 Amp fuse is plenty for the starter or joining the batteries. I've never blown a 150A fuse.
I recommend a 250A for a strong 12V winch.
Toyota didn't use fuses on the starter or on the joining...
I used the old cap on the new master. Fit perfectly. The old cap has a floating donut that induces an open or closed circuit into the low brake fluid sensor.
Its possible that the cap on the JDM HJ's are a different diameter than on the US FJ's.