Everybody seems to be well aware of the advantages of OHC,
A few of the responses make me think, they never considered the advantages of pushrods.
You can design all kinds of things.... but what do they cost to make? How easy are they to work with? What happens when this or that fails?
50 years ago I can image many smart alec remarks about how putting camshafts in an aluminum head.... is a fools errand.....and in many ways it is, but just because it's hard doesn't mean you can't do it. You can do lots of things the hard way and make it work, especially with a good reason.
Half the stuff on the street is doing it it must be easy......well, actually it's pretty amazing.
I assume the reason the LS engine is a pushrod V8 because the designers were classic gearheads, who liked pushrod v8s
