For near equal dollars to build 250/292 that would make 275HP, a 4200 can be had and installed. It is more work to do the 4200, the flip side you end up with a relatively new engine design that is not to difficult to turbo later if you so desire.
A 4200 running 10# of boost can make 425/450hp with no internal changes other than a good tune in the PCM and bigger injectors.
Last edited by efi-diy; 05/23/17 11:06 PM.
