Hey guys I have a couple of questions regarding using a 350/403 Olds in place of my 307 in my 87 Caddy. Would the 350 motor bolt right in and would I be able to use all the accessories/brackets off the 307? Also would the intake/carb/distributor/harmonic balancer off the 307 work? What mods would I have to make? Thanks in advance.

Yes, Yes, Yes...

All Olds small blocks will interchange. However, does the Caddy have fuel injection? If so, then the computer MAY have to be re-programmed for added fuel delivery (if Open Loop).

You would need the balancer for the engine you choose to use--as they are different...

Further, tranny may have to modded to handle greater torque.

See the engine FAQ at 442.com. I'm swapping a 403 in place of the 307...