Chevrolet made the 235 engine way back in 1941 for military trucks.
Chevrolet began installing the 235 in cars about 1950.
The valve cover design changed in 1954.

http://chevy.oldcarmanualproject.com/shop/1949_53/06engine/6_062.HTM
14 psi at 2000 RPM for all 1953 engines, except Powerglide equipped cars
45 psi for 235s in 1953 Powerglide equipped cars.

As Mike B said, engine serial number prefix LAQ is Chevrolet passenger.
A 1953 Corvette would have a LAY prefix.

You said, "The truck was purchased with a stuck 216".

A 216 is a Chevrolet engine that is in a GMC truck. How was the engine mounted? Pictures?
The reason I ask, and I don't mean to criticize, is that GMC engines are longer than Chevrolet.
The GMC front crossmember is further away by about 2 inches.
This negates the idea to use the standard truck mounting position on the front GMC crossmember for Chevrolet engines.
After 1951, Chevrolet car engines were mounted on the sides near the front.
Years later on, mounts were moved back to a mid point.
The importance is that you may need to fabricate front mounts.
Also the location of you water pump cooling fan in relation to your GMC radiator should be investigated.

"Adding CFM to a truck will only help at engine speeds you don't want to use."
"I found there was nothing to gain beyond 400 CFM."