I don't want to hoon along the highway at suicidal speeds. I would like the extra power to crawl around the bush a bit, possibly towing a little trailer.
TT,
If you just want to get around the bush, especially if traveling by yourself, then I would suggest staying away from over powered 1275 type engines.
Having too much horsepower in the bush, especially hilly country around NSW, has two issues.
Too much torque at the wheels in a Moke can mean a lot more wheel spin than you need leaving you at the bottom of any reasonably steep slippery hill. Of course you can gain extra traction by going up backwards, but not a got option with a trailer.
The bigger issue is having the extra HP from a worked 1275 now gives you enough power to break minor items like the ripping the diff out of the housing. With a smaller HP engine in the bush you are going to stall before you break anything major.
A standard 1275 Moke from the factory is fitted with thinner drive shafts than the ones commonly found under most Mokes and Minis. The idea is that when the torque exceeded expectations it would break the drive shaft rather the diff and related items. Most people who transplant a bigger engine I would doubt they replace the shafts to suit, however for most road applications, other than drifting, this probably okay. Diff selection also reduces or increases the risk of hearing bang you don't want to hear.
The other thing to remember the diff and diff housing in your gearbox was designed with tolerances given for a 850-1100cc engine running 10" wheels. Introduction of 1275 and 13" wheels didn't see any major enhancements in the drive train.
So buy your lotto tickets and in the meantime just be smart when driving in the bush.
Try not to travel alone, more fun with more Mokes anyway.
Don't go down any roads/tracks you don't think you can drive back up.
Short slopes can be tackled, but long steep hills may see you run out of ponies before the top. Turn around try again backwards and you will get a 50 odd metres further :-)
Mokes are not 4wd's, but will go many places they can.
Ditched the sump guard, if you have one, and save weight abd gain clearance.
Of course another solution is to convert your output shafts and axles to use the original rubber uni joint set up and they will break before anything else and are easier and cheaper to fix on the side of a bush track :-)
Terry