So I have a 99 Chevy Tahoe and I’m hoping to take both engine and transmission from Tahoe and install them in a 86 Chevy caprice. What all will I have to Consider When making this change?

 

I know I need a engine starter plate kit But due to this covid virus I’m at a stand still with the order
wish it was another alternative besides retapping or welding

 

If the '99 Tahoe was a Vortec instead of a 5.3 or 6.0
LS-series (at that time pickups were LS-series, vans
were still Vortec) then it's likely a pretty straight swap
on the existing mounts, mechanically, but you'd need
the PCM and harness. The LS family probably needs
conversion mounts (at least, these were a thing in the
4th gen LS1 Camaros if you wanted to go the other way).

Oh, and a high pressure fuel pump, regulator, whole
set of lines if the '86 Caprice was carb'd.

Starter should need nothing as it would come with the
motor / trans combo?

 

I would swap in an engine/tranny combo, but be forewarned length of driveline will likely change so your current driveshaft will not work, and if you increase weight significantly you'll have to bump up brakes and springs. 305 and 350's share the same block, so no significant changes there, can even use same engine mounts.

 

Re driveline length, my '75 Caprice has cheerfully accepted
a "built 700R4" swap in between SB400 and stock driveshaft.
No messing with anything in that regard. Bit of a chore to get
the speedo and TV cable stuff right.

Though there are multiple tailhousing options to check on
both accounts.