I was just curious if anybody has done the swap to put a 454 in a 1990 4x4 suburban before? It wasn't an option on 1989-1991 subs due to some crossmember or other design problem... It has crossed my mine to upgrade from a 350-454. Was it a lot of trouble or costly? Thanks! 454 in a 3/4 ton 4x4 was never a option. GM would not put the 3/4 ton front axle behind the 454. They also put ff14's in 454 trucks in the 80's. If it had been a 350 truck it would have got a SF 14. GM would not put the D60 in the Sub so 454 was never a option on 4x4 burb till the 90's.