[andyh1956]

i think to make the 230-250 head breathe better you cut out the "tunnel" the center head bolt goes through & use a stud & nut in the intake port. the dirt trackers around here about 20 years ago were taking two small block heads & cutting the end cyl off & welding them together. they bolt on & that gives you a crossflow head. don't remember where they got the manifold or if they made it. been away from that stuff for a long time.
andy
p.s. a 235 will fit where the 216 is in your '52. and where a 235 fits a 261 will too!