68Catanlina707

New to the group and looking on a little info to put me in the right direction of putting an LS in my 1968 Pontiac Catalina Fastback. Basically I am looking to upgrade the suspension and interior with 90s Impala upgrades with digital dash. Under the hood I'm looking to put the 5.3L or 6.0L engine with matching tranny from a 2WD Silverado. My question is does the truck oil pan clear the crossmember on the 64-70 GM B Body or is a modified oil pan needed? Also would using the gas tank from a 91-96 Caprice work on this application?

Any suggestions or input is appreciated.