KZ650 Engine Swap Candidates/Build questions

Howdy, y'all. First post here.

I have a 77 KZ650, and I'm looking to either swap the motor or build up the stock 650 block.

So, what will fit in the frame and mate with the existing transmission? If those options aren't viable, what should I do to the existing engine(Stroker, head swap?) Perhaps a different carbeurator set? Not a racing bike, just a little touring bagger I'd like to build up.

Search function didn't reveal much, but I'm new to it anyway. Eh.

A KZ750-4 chain drive engine is a direct fit. Maybe the GPz 750. not sure.
Within the realm of possibility a 90s Zephyr 750 or ZR-7/ZR-7S (ZR750 air cooled models. 2000-2004 or so).
Those models have a Hy-Vo cam chain, 3-phase charging system, & electronic ignition. 75 hp or thereabouts.
You could keep the stock carbs & rejet them n stuff, or go with the carbs & airbox from a 750.

First thing you need is a manual. The engine and transmission are one unit. Before doing any mods, it is best to get it running good. You can make these things more powerful but if you want more than that, get a bigger bike.
Steve

700 cc kit and 750 cam livened up my bike but wish I would a went to 810 while I was doing it (google KZ650 to 810cc and put down the forum)...... things add up fast pistons, complete head, gaskets, cam chain, rollers, clutch (starter clutch assembly so you won't have to do it twice) etc etc then you still have tires, chain and sprockets, header, and suspension, brakes and all of a sudden your well over a couple grand....... to be honest closer to three..... A 750 swap like Martin says is a good possibility if you find a good runner Zukerdave is kicking rear with a GPZ 750 motor in his 650 frame.....I like Steve's advice too.

I'll say it again best money spent on turning up the power in a KZ650
is a KZ/ZX 750 motor swap.

Mine hell ya it's a quick little bike but I got a shit ton of time and money in it.