Quick... which way's better (225/273)

WHAT WOULD YOU DO??

So I bought my 67 Valiant a few weeks ago, she's got a so so tired 170 that smokes and power of a manual wheelchair.
Since buying it I have been pretty set on building a 225 with internal goodies to be paired with a turbo... maybe a ~300hp range build because I want it streetable too.

THEN this lil guy popped up... a 273 small block out of a '68 Satellite. Unknown miles but ran when pulled (like they all say lol) however it is a pretty clean motor, stored in a storage unit with plugs in it and all the open ports taped shut (intake, exhaust, thermostat housing, carb, and even the valve cover breather holes) meaning stored nicely I guess is my point.
Engine is complete oil pan to valve cover, has a cast 2bbl intake on it and a distributor too but no carb.
It ALSO comes with a Holley Street Dominator 4bbl intake that's clean too.


MY INVENTORY ON HAND:
(In car, 170 with a 3 speed floor shift converted)
A rebuilt 4 speed A body A833 transmission
2 Bellhousings:
1 to put the 4 speed behind the S/6
1 to put the 4 speed behind a V8

Valiant already has 11" front disc brakes and a 8.75 (3.23) suregrip rear end.

Besides exhaust and motor mounts (which I see now companies make slant 6 to V8 mounts so I don't have to switch my K member) what else will I need?
Drive shaft the same length? Crossmember different? She already Manual steering and brakes so nothing to worry about there... anything I am missing?

What do y'all think I should do, WHAT WOULD YOU DO?... pull the trigger and go with the 273, build it, maybe turbo it too... or stay with the 6 and WHY?

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