I took the 76 454 silverado to my moms today, about a 20 mile drive on the interstate. The truck did fine, but when I started to go home the truck tried to stall out a couple of times and then had a very low knock that has not gone away. I drove the truck back to my moms and that is where it sits. I am just wondering if the fuel pump may be failing would this possible cause this knock? If not I guess I'm looking at a rebuild. Darn I knew it ran too good when I bought it lol.