if your looking to stay stock and have a little higher hp and have a reliable car, you might want to buy a car that has the 400cu. not the 403. the reason is that the 403's had a thinner walled block than the 400 so if you ever ended up building up the top end with cam,lifter etc. you would probably blow out the bottom end. A stock 400 in 76-79 was around 180hp, 360lbs torque, definately a freeway flyer but a nice cruiser. The turbo T/A's in 81 put out about 220 hp stock with 301cu block. like hughjass said it takes some dough to build any engine, but i just bought a 1974 400cu motor w/ 400hp, 10:1 compression and only 30,000 miles since the rebuild all for 1200 bucks. So you don't need a ton of $ to build a pontiac 400 into killer. hope this helps