OOOH, someone got out of the wrong side of the bed. Maybe time for an afternoon nap today, get your beauty sleep, eh.
Earlie A was comparing two heads and mentioned valve sizes. I just post a possibility that is inexpensive to a degree. Yes machining to put the 8mm guides in is costly. But good chance those poly heads are due for guides anyway. Whether you chose the Magnum or LS valves, the smaller stems provide much lighter valves. I would venture the LS have a lower cost.
Intake flow is area ruled up to a lift of 1/4 the effective valve diameter which is 0.91 × measured head diameter. So a 1.84" valve has an effective seat diameter of 1.6744". That × .25 is about 0.42", so the valve is in most cases the limiting factor in port flow up to that lift. At higher lifts the port flow is more the limiting factor. Old engines only had about 0.375" lift, so big ports were not required. Stovebolt Chev 6's only had 0.3" lift, definate tractor engines.
Your choice what you want to do with that information.
