keep the 283!!!!!!!! take the 283 bore it .125 over to 301.6 and if you want it knarly put some dz-302 pistons in it a 302 crank and rods and the offroad cam isnt bad either. or if you like you can use a lower compression piston and you can ahve a better gas motor. dont let anyone tell you the 283 is useless. i have one it is bored .125 over with 302 internals it runs damn good. so keep that 283!!!!!!!!!!!!!!!!!!