Keep the 292 or swap to a 400?

[Truckdriverjames]

I picked up a 67 C20 2WD with the 292 I6 hooked to a SM420 (I think) and a noslip FF 14 bolt with stupid low 4.57s ive got a newer FF 14 with 4.10s a SM465 and a running 400 SB with the frame perches and motor mounts left over from a previous Willys project. The 292 runs but its got a rod knock starting but i think its early enough that it hasnt ruined the crank. Im new to the whole Chevy thing just seeing what yall think?

Thanks!