4.3 to 4.8 or 5.3

[mcdad1979]

everybody i have talked to says gm never used the nv3500 behind the 5.3 cause the engine produced to much torque for that trans.

[johnmichael397]

i have a nv3500 behind my lq4 and it seems to be holding up fine. But mine was behind a 350 before if that makes a difference.

[Frenchy]

In '99 the 5speed did go behind the 5.3. Very rare though. You'll need a flywheel and clutch for a 4.8 5speed truck. I used a Centerforce clutch. My truck started 4.3 5speed too. Now it's a 5.3

[mcdad1979]

thanks for the info i will for sure be doing the 5.3 now. one more question if i get the ecm from the donor truck will i still need to get the ecm reprogrammed for my truck?