Howdy 57chevydelivery and welcome to the 'Bolt, by the way.
We're not trying to give you a hard time here, it's just that you're the first one to ever ask this question (that I know of). I think we're all having a hard time understanding why you would want to do this "upgrade."
Is the original engine bad? Do you have a 4.3L already? Even newer straight sixes, like the 235's from the mid to late '50's are easy to find and would be a heck of a lot easier to install (I just gave one away ...). Even if you already have a V-6, finding a good running pressure oiled 235 (and buying it) is still a preferable solution to the aggravation of trying to make the modern V-6 work.
Just a thought. It's your truck and we're just offering ideas here. Tell us more about this project of yours! Got pictures??
Regards,
John
