(Newbe) 273 to a 340 and tremec 5speed swap.

TKX still needs to have the crossmember removed even if it is more compact than a TKX. Not as much floor pan work, but not a bolt in either.

The right TKO might have the mods to keep the crossmember like the kits from Kreisler did but the output shaft is low if the crossmember is kept. Workable, but not ideal.
think im going to just sell it if I end up buying this engine. thankyou for your comment,
-George.