So within the next few months I plan on having enough money to tear down my 3.4 and having it rebuilt,
I plan on doing the 3400 swap so besides the parts needed for that(heads/intakes/pistons), what else should be replaced?
alsoone more question...
is itpossible tohave PCMforless tune my computertofurther compensatethe 3400 swap in my 94?

 

PCMforless can't tune a 3.4L computer.

Megasquirt and FAST are the only tuning out there.

Or just run it stock and hope for the best.

 

You also need push rods, & the 3400 roller rocker arms. You may also want go a little larger on theinjectors. You can use the 3.4 pistons, but the compression will be up in the stratosphere, otherwise go with the 3400 pistons. It will probably be lean with the 3.4 injectors @ WOT if you don't get a tune. The new heads do not need as much total spark advance as the 3.4 ones, and for this reason it will work much better with a tune.