What are the best options?

 

probably a 20 R.

I just swapped a 20r and 5 spd into my 67 Stout and it was close to bolt in...used stock tranny and engine mounts only having to use some steel as "adapters"

 

what about a 22r? is it possible?

 

a 3L engine?

 

Should be pretty much the same...22r and 20rs share the same mounts so I would imagine it would be exactly the same.

 

I've seen an a Mercedes OM617 diesel swap and would love to see a VW 1.6 or 1.9 TDI swap into a 79-83 2WD. Haven't heard of anyone who's done one yet

 

I've also heard that the 18-R is a relatively easy swap which would certainly give a good improvement on power, or a twin cam 18-RG if you can find one.

Anything is possible...depends on dollars and the motivation factor I guess!

 

I was going to say the VW TDI engine, somebody on the forum here did it into a pickup, there is a build thread I will try and find...

 

5R 2000cc 106hp bolts straight in...

5R 2.0 L (1,994 cc) 106 hp at 5,200 rpm
12R 1.6 L (1,587 cc) 90hp at 5,400rpm
18R-C 2.0 L (1,968 cc) 97hp at 5,500 rpm
18R-G 2.0 L (1,968 cc) approx 135 hp at 6,400 rpm
20R 2.2 L (2189 cc) 96 hp at 4,800 rpm
22R 2.4 L (2,366 cc) 97 hp at 4,800 rpm and EFI 105 hp at 4,800 rpm

both the 12R and 5R are low compression OHV engines that easily have the ability to far out perform many engine transplants, i have read things on the 12R in the corona where they have been used in rallies and as race cars.
my self i have heard nothing on performance mods to the 5R but it is an ideal motor for some serious boost levels as the motors them self are verging indestructible (timing chain version). one i have has near to 1 million killometres and has only ever had a head gasket replaced, due to having a look.