Thinking of a Project,, Mojave Frame GS500 engine or CBR600?

[400exredrider]

Hey guys, im thinking of doing a little project, ive been looking around at Motorcycle Engines and you can get a decent one for a good price, heres what i wsa thinking,, mojave frame or blaster, something small and cheap, and a GS500 Engine, i was looking at the EX500 but the radiator would be a tight fit, GS500 puts out around 40HP and the Mojave weighs about 388 or so with the stock 250 in it, so id say that engine is what around 50-60 lbs,, id like to keep it below or around 400 dry, a blaster would work too but it would be too small for me, Ive also considered going with a CBR or even a GSXR 600 4 cyl, the CBR600 seems a little bit shorter and it has been around a little longer, i just dont know if the frame would need too much tweaking, i want it to be strong, a CBR600 would be insane power for the little mojave frame so im sure some swingarm adjustments would be needed, also thought that a fat ol polaris trail blazer or a scrambler fram would work nicely for a 4 cyl... i could gut alot of stuff off of the polaris plastics,,, trim the fenders down, chop the running boards off , and try to get a 4 cyl in there,,,, ive seen it done but mostly done with alot of modification to the frame, id like to keep it simple, see if anyone on here has tried it and see what you guys think.

Thanks