I personally swapped a 4.3 in to one of my old zuks. I liked it, but tend to agree with the other guys that it is a bit heavy. With that being said, here is my magic junkyard list to help you if you go that route.
Manifolds - Stock 4.3 manifolds from trucks and van's will not fit the frame. However 3.8 Chevy V6 manifolds from a 1978-87 G-body car bolt to the 4.3 and will clear the frame nicely. Make sure they are from a Chevy 3.8 (distributor in the back) and not a buick 3.8. If you can find them, get them from a car built in/for canada, as they do not have the smog pump holes that need to be blocked off.
Trans - this is a personal preference thing, but here is what I did. I used a 1985-1991 Chevy fullsize truck hydraulic bellhousing. If I did the swap again, I would get one from a 1992 truck (or use a nv3500, which I'll explain later), as the slave cylinder is on the opposite side. In my case the slave cylinder hit the drivers side floor just under the pedal and I had to clearance it. Otherwise you'd have to go with a two inch body lift to clear. Then for the transmission I used an S-10 T5 five speed manual from a 4x4 2.8 truck with a 13 spline clutch disc from a stick shift Astro van. I then made a simple plate out of aluminum that bolted to the back of the T5 where the transfer case normally would and put a two wheel drive T5 oil seal in the middle of it. This gives you a five speed manual that is 6 inches shorter than a two wheel drive trans. A two wheel drive slip yoke from an S-10 then slides into the back of the 4x4 trans with no issue. If I did the swap again I'd use an S-10 4x4 NV3500 and make the plate again, as they have an integral bellhousing with a passenger side slave.
I did have to clearance the trans tunnel by widening it approx 2 inches to clear the trans.
I then had CCI make me up a short driveshaft using an S-10 2wd yoke and the back of the zuki intermediate shaft. This bolted up to the Suzuiki T-case. However I did have to rework the Suzuki T-case mounts to push the T-case back about 4 inches for additional clearance. I put on 2 inch lift leaves and a spring over swap, netting me about 7 inches of lift. By redrilling the mounting hole on the spring plate to push the rear axle back about 1 inch, I was able to use the stock rear driveshaft.
For motor mounts I just fabbed up my own out of stock 4.3 mounts.
Stock 4.3 water pumps will not fit. You will need to get the short water pump and accesories off a 1955-1967 Chevy small block, or 1955-1985 Corvette. All the pulley and such will need to be used.
For a radiator I then used what I believe was a radiator out of a Chevette. It was almost a perfect fit. I then used an electric fan, and everything fit without cutting the firewall.
I think that was about it, if you have any more questions, shoot!