1.5" or 1.65" Rocker Arms ?
 

on '69 RAiii 48 heads?

Thanks, John

Are you asking if that's what came originally or if you can use them? Originally, believe only RA IV & some HO heads got 1.65s. If you can use them? If you enlarged the pushrod holes, in most instances, yes, you can use them, though to be sure, you'd need to check retainer clearances, etc.

.

Thank You, that answered both questions.

1.65's are going to raise the lift 10%, and sometimes there just isn't that much room to coil bind depending on the cam. As HWYSTR455 mentioned, you could also have retainer to seal contact.

The 1.65 rocker arms are exclusive to the '63 and earlier Super Duty engines and '69 -'70 RAIV.