What does the 401 share with the 478? Just swapping in a 478 might be the best “hotrodding” plan.
EDIT: they share a lot, likely one bolts in place of the other.

Last edited by Grigg; 02/14/2019 2:35 PM. Reason: more info
•1951 GMC 250 in the Project Journals
•1948 Chevrolet 6400 - Detroit Diesel 4-53T - Roadranger 10 speed overdrive - 4 wheel disc brakes
•1952 Chevrolet 3800 pickup
---All pictures---
"First, get a clear notion of what you desire to accomplish, and then in all probability you will succeed in doing it..." -Henry Maudslay-