"I had been told the radiator mounting tabs that run vertical and attach the radiator to the core support themselves were a different offset between V-8 and the 6 cylinder"
no - the 55-59 rads are all identical, an "H-55" will fit any year, 6cyl or 8
for the 55-57, note assy man sect 13 sheet 5-14 for 6 cyl - RPO 408 sheet 4-5 for V8 ... the small brackets that the core support bolts to on the frame are moved back for the V8 [riveted on 6cyl trucks, bolted on V8 trucks] - if I remember right, the front hole of the bracket moves to the back hole on the frame, about 4" - then there's some special sheet metal that fills in front of the rad as shown in the RPO
I've never seen a 58/9 V8 that I'm sure was factory, but AFAIK the mount points for them stayed the same 6 or 8, and they had a fan shroud for the V8
all TF 6's mounted the same in relation to the cab, and the rad was about 3/4" from the fan - the 265/283 is 4-5" shorter than the 235, so 1" forward difference isn't understandable, the shroud was only about 3"
I'll measure someplace on my 58 frame tomorrow and let ya know
Bill
