How do I get 400-450 hp out of my stock 78 Z/28 350ci engine?
Without snapping the cast iron crank

 

Easiest way would be to put a 383 rotating kit in the block, top it off with a good set of heads/intake/carb, and a good exhaust system. 400 easy with a mild cam, 450 with a rowdier cam. You can do it with stock cubes without worrying about snapping the stock crank, but just not as easy, and it won't have the torque of the bigger cubes.

 

yeah I'm not planning on swapping out cranks and pistons. I don't know how to change all that I'm mostly familiar with just bolt on stuff like intake, carb, heads, and cam. Do you know what parts I could bolt on to get that kind of power? Like vortec heads and victor jr intake? thanks

 

heads with 200cc intake ports and 54 cc chambers.iron would work.
cam with 300+ duration,525+ lift,non roller would be fine
victor jr or team g intake
750 double pumper
some good rings
good gaskets, not the 26.95 autozone ones.
stock pistons and rod bolts wont live long at this power level.

 

Hopped up Vortec heads,decent cam like mentioned above,Perf. RPM air gap intake (hood clearance permitting),and a 750 DP Holley.

Oh yeah,and a good set of push rods .

As long as you can keep the revs below 6500 the stock rod bolts should hold up for a while,but shifting it around 6000 and below would be ideal.