All 302 engines are more or less the same.The D head was the original head on all 302's,it has a D shaped combustion chamber similar to V-8's of the same time period.All 302 cranks are forged steel,they were induction hardened for surface strength at time of manafacture.Turning the crank for oversize bearings removes the hardness,but it doesn't seem to matter for the way guys use these engines today.
A moderately tuned 302,hotter cam,more carburation,higher compression,headers,etc,will make around 225 hp,more money spent on some headwork will give 250 hp for a streetable engine.There are all out race 302's making fantastic power,but they aren't streetable.
These engines are expensive to build properly,a liitle more power costs a lot of money.
I have a built 302 in my 37 Chevy pu,the estimated 240 hp moves this 3000 lbs truck quite nicely.It gives fits to the kids in their stock 90's V-8 Mustangs,and the torque will surprise sleepy drivers in 350 hp Camaros.But once they wake up and wind up the engine,they do pull away.
302's are vintage engines and for street use are somewhat RPM limited,but are the best vintage inline engine.
If you wanna get serious,I believe a 292 Chevy can make more power for less money.
