bobby7821

Im building a 95 mustang for my son the cars in need of a motor i planned to rebuild the 3.8 but i,ve research a bit on the 4.2 what i gather is that there preaty much the same engine exept the 4.2 has a longer stroke but retains the same bore i plan on useing a m90 sc supercharger set up i bought the other day i have every thing to swap it to my sons 3.8 but if i can build the 4.2 and use the supercoupe heads than i should not have any problems my ? is are the blocks the same do they share all the same mounting points will the super coupe heads work any help would be great thanks

NeoTokyo

They will swap over just fine.
The SC uses stronger rods and pistons though I beleive so you might want to think about updating that area too.

LilRoush

A well done single port M90'd 4.2L can put down over 400 rwhp.

Waldron93

should be fine.. your sons lucky.. i can only swap a 3.8 for a 3.8