big block tbi help!!!

[1972BackInBlackC10]

i know there are several posts about this topic but i didnt want to highjack someone elses thread and their questions werent really related to mine, with that being said

i found a 454 tbi for 1000 bucks and i can take everything i need, ecm, wiring harness, rad etc

my truck had a 350 with th350 combo with the motor mount bolts that go into the middle from the bottom not through the sides, im wondering if i should get the engine mount stands from the truck the motor is in (its a 91-93 cant rememer for sure) or if theyd work, or some from a 73 to 87 model

also should i use my th350 that was in my truck i have a shift kit and high stall torque converter for it, just not sure what trans combo to use i dont want to hve to mess with my drive shaft much, meaning i dont want to have to make it shorter

thanks for all your your help/input in advance