Okay guys I am getting my money together to get some of these "christmas presents" for the car. Now I am committing to some vertical link bar lifters for the hydraulic roller retrofit into a 1974 351 Windsor. I just want to confirm from the experts that these will work with a standard base circle cam before I spend $420(I just don't understand how them being vertically linked doesn't require taller lifter bores, if possible I would like someone to explain it to me), if not I would rather do spider and dog bones assembly. I am also calling summit racing to get help from their tech line, but want to be safe and check with you guys too. Here is a link to the part: http://store.summitracing.com/default.asp?target=partdetail.asp&part=FMS-M-6500-S58&FROM=MG