I had a 1975 FJ40 from 1987 until last summer. I’ve had two 350 Chevys in it. The first was carbureted and the second was throttle body. For the first engine, I modified an aluminum Chevy bellhousing and mated the four-speed transfer case directly to it, utilizing a custom short throw clutch set up with internal splines to match the four speed transfer case’s input shaft. For the throttle body engine, I used a Chevy cast-iron bell housing with some internal changes to the stock transfer case and attached the transfer case to a granny low Muncie 465 trans with a custom adapter I fabricated.
If you are using purchased off the shelf components, your job should be much easier than the route I took. I fabricated motor mount brackets, a rear mount that attached to my adapter plate, linkage modifications, etc.
If you are fabbing your own components and deciding for yourself the exact engine location, it was helpful for me to use a bare short block to bolt things up and move them to the optimum location prior to welding the mounts in place. I recommend having some clearance to the firewall so that you can access the distributor, but that has to be balanced with keeping the cooling fan sufficiently away from the radiator.
I used the stock radiator for many years and never had an overheating problem, but I live at 6200 feet plus and my four wheeling is pretty much all above 5000 feet. I don’t know how I would’ve done in the south, for example. I always ran a healthy shroud which I made from galvanized sheet metal. Nothing fancy. I also used the biggest five blade mechanical Chevy pick up fan from that area with a fan clutch.
I’ve broken several small block Chevy motor mounts, but it never presented a problem on the trail because they have self securing mechanisms. The engine can move around a bit, but it was not a problem. Those are pretty easy to change.
if you are using a TBI engine, the best results will be to use an in tank fuel pump. I never got around to installing one and I had to make sure the hose clamps on the suction line from the tank did not loosen up. I’m sure that options bound for an in tank pump. I found one in a search through the 40 tech section being sold out of a car dealership back east somewhere that utilizes the holly sniper pump, complete with detailed directions as to its precise location so that your fuel tank cover will still fit over the tank.
Other build features included a four link rear coil suspension of my design that I built and installed in my garage, Saginaw power steering, A Blazer tilt steering column, Mazda sport bucket seats, full roll cage built by Redline Land Cruisers, ARB’s front and rear, and rock sliders I fabbed.
I know that many in our 40 community love the 2F and many love the small block Chevy. To me, once the Chevy went in, there was no turning back. Like someone said above, let the party begin.
I sold mine because I am getting up in years and my body is getting too creaky to work on my 40 like I used to. I found a nice low mileage equipped 2001 LX 470 and purchased it from a mud member. Sometimes I miss my 40 as it outshined everything else on the trail, but life has moved on for me and now I need the creature comforts and people hauling capability. Good luck on your build.