300 horse should not be a problem, but it will not be a cheap build. The block on the 292 does not match any of the other sixes in the series 194/230/250, it is about 2 inches taller. The bolt on parts that fit the 230/250 will fit the 292. There were several cranks used in the 292 from the factory. The early 292s had a forged crank the later used a cast crank eithe 6 or 12 counter weights. There are no other cranks available AFAIK.
I would suggest that you go to inliners.org and do a search. Look particularly for tlowes Dyno Day test for the 292, he tested a multitude of parts for a street able 292, 300 hp was the upper limit. For an alternative you might look for EFI-DYI 4200 turbocharged and EFI build, he is almost most finished. The last dyno run got 500 hp, 500 torque, before the worked over 4L60E destroyed it's tail shaft.
Larry
