bore and stroke

ABOUT how much of a horsepower gain can I get from bore and stroking? I have a 145HP, 147ft-lb F22B1 (VTEC)?

it depends on what you do. most people change the bore for more displacement. the ratio is changed to optimise effectiveness according to application. 1.75 is the best ratio for high reving engines, less than that is good for turbo or supercharging like 1.6 or so. too low a ratio and there will be lots of side wall effect from the pistons rubbing on the cylinder walls instead of going straight up and down. you need to read up on this. stroking is very expensive. it is much cheaper to buy a different engine.