91 old school swap

[Tx Firefighter]

I've done this swap a few times.

V8 mounts will bolt to your existing crossmember once you remove the V6 frame mounts. Then the engine will bolt to the trans and no driveline mods will be needed. The existing flywheel, clutch, bellhousing bolts and starter will bolt onto the 350 as long as it's a one piece rear main seal engine (newer than 87). If your V8 is a 2 piece rear main seal engine you will need to change the flywheel to match.

To do it right you'll need the proper V8 fan shroud.

The lower (crankshaft) pulley will need to be swapped for the proper V8 one as the V6 harmonic balancer is thinner than the V8 one so the V6 pulley is deeper dished to compensate for the skinnier balancer. Everything else on the front of the engine is a straight bolt on to the V8.

You can reuse the existing V6 ECM and wiring harness as long as you install the proper 350 PROM chip into the computer. All of the plugs on the V8 will be the same as the V6. You will need to slightly pull the wiring harness further forward into the engine compartment to reach all proper locations on the V8 but you won't need to mod it.