Many thanx for the reply Skrews!
I only asked about factory 'tulips' as I saw somewhere else that Mopar S/B heads were designed with these specifically in mind?
I don't have a flowbench to find out any data for myself and like most folks, just do 440 yard test runs lol.
Reading this an other very informative threads on 'A-bods', J heads are good and can be great, just don't touch the SSR!
Judging by your extensive guide boss work, it seems you can leave some 'cast-in' metal behind, as long as its a nice shape.
Many thanx again form the Limey