The early, low pressure (1941-1953) 235s had 2 center-top-bolts valve covers.
High pressure & low pressure 1953 235s had 2 center-top-bolts valve covers.
No high-pressure 235 was used a USA truck in 1953.
A high-pressure 235 was used in the 1953 Corvette (and, I think in Powerglide-equipped-235s) - the Blue Flame Six (painted a light blue color).
1954 and later 235s (and all 261s) had 4 side screws valve covers.
