[242177P]

I'd like to think that one could successfully argue that they borrowed some stuff from Pontiac's playbook when they created the LS1. The SBC had a 23 degree valve inclination, the new motor used 15 (Pontiac went with 14 back in 1967).

SBC ---> 4.00 x 3.48
LS1 ----> 3.898 x 3.622
350P ---> 3.875 x 3.75

Well, that *could* just be a coincidence.
So let's look at the 427.

BBC ---> 4.25 x 3.76
LS7 ----> 4.12 x 4.00
428P ---> 4.12 x 4.00

I'd like to see what a baby roller would do in a 350P. A well thought out grind would yield respectable mileage numbers and really breathe some life into it. That, IMO, is the biggest advantage the LS has. Yeah, they've got big flow numbers, but the cam is key. Imagine how much they'd suffer if they were forced to use a HFT with 1.5 rockers.