Making room for push rods is normal on any aftermarket head unless you use a 5/16ths--which with hyd cams is fine-- but most builds will require a 3/8ths pushrod--any Mopar requires lots of time spent--shimming each pair rockers--getting it just right--centered on valve as close as possible while clearing the head and all the while winding up with proper side clearence per pair on rockers--each pair may be shimmed different--that is Normal--grinding for more room is very normal operation an any build. Wait until you get smart and put 1.6 ratio rockers on with a big cam--Lots o grinding there!!
I have been dynoing plain old 440 street engines with Sidewinder heads--looks like with bigger hyd cams they are doing easy 530 range on simple flat top pump gas combos--these have been with STAMPED stock rockers as well.
Low you say?? I say cheap and simple and enough HP and monster TQ to rip quarter pannels off.
90% of customers have NEVER had any real HP and over 500 REAL HP makes them shake after a ride--as it SHOULD! The quest for all these 600-700HP street engines is a laugh to me--you can't hook it up--they are a PIA to drive with all that converter , gear etc--Street driving a race engine has never been as fun as it is rated--like driving the Zamboni on a skating rink.
Just my two cents worth--Call Todd at Marsh, get some Sidewinders and enjoy not paying the extra $600 for Edelbrocks and going same speed.
Same head everywhere no matter the name--buy a skid of them and you can name them anything you want--we are LUCKY to have a quality head that is less than the others out there--Source heads are brittle castings to me--these heads have the guides centered Right ON and are all CNC finished--I have been using them like popcorn and Todd at Marsh Performance has Kept them coming!!!!