According to Hal Needham, the actual stunt coordinator
who ordered the build, for several films, & a couple of "hero cars"
it wasn't what it came with either,
doesn't even matter which year the car was, it's not stock
there was a bunch of them too, like 3-4 in each film,
some cheesy/cheap POS's, base crap 351m or even 2v
that are wreck eventually, just base motors/auto etc.
doing the stunts
(
look in the credits cars (& parts ?) were from Ford Motor Co. for advert. considerations in filming)
The "actual cars", being driven varied, from POS's for stunts,
w/cages & some with different suspension & a few "hero cars" (like the BB cars)
over the 3 film series
Hal Needham he was the one who said;
it was a 429 SCJ with the tunnel-port heads,
2x4bbl & BW T-10, 9" rear
Just like the stuff Burt said when they filmed the documentary special/s,
Lure of speed (Burt & Hal the Mach 1 racing story)
Behind the Scenes (Hal Needham journey from stunt man to director),
The Bandit sneak (CMT documentary with Hal & Burt),
**I think that was close to the names anyway
there were a couple more I don't exactly remember the names
it was all after
they made Smokey & the Bandit, talked about it, & touched on several films
getting into racing too
watch their several documentaries, they're pretty good,
I haven't watched them in quite a while, could be mixing quotes/the facts up

don't quote me, it's just a damn car forum, post
there was another on Dina Shore's TV show, (who was Burt's former old GF/squeeze)
I rarely believe them click bait videos ever or at all, like the one posted
or what was shown on some screen shot on camera, some dude pushing paper remembered
(
just like that BS story "about an alleged 4 dr 'cuda" from some random unknown no name 'dude'
said; he "allegedly" saw, allegedly was some employee from the Chrysler/Plymouth mail room BS
)
it's the movies
that usually just speculation BS, on film or bad continuity, most people don't notice
just some shot of bling for the cameras & is rarely correct info/facts...