why guess? wouldn't it be better to get some books and learn about what you've got and what's possible with a small block before fantasizing about goals? or maybe you should pick the brains over at
the HAMBa friend here built a 427
for his 55 - not likely it puts anywhere close to 400hp on the ground, but it'll pull the front wheels, and I can tell you it doesn't take much of that to trash bearings and break spindles ... what's the point? certainly doesn't make for a daily driver, especially the way gas prices are going
a stock 283 would be rated @ 195hp max depending on the year ... which will spin tires and blow transmissions, u-joints, and rear gears that are not 100% ... good luck increasing it to 300 - and getting more than 1/2 that to the ground in an old truck
Bill