I don't get the 9.0:1 Street Hemi idea - the chamber is not that sensitive to octane.
That's a fundamental reason Chrysler introduced it for the '51 models.
I ran 10.8:1 in mine with iron heads on Calif 91 and it never rattled.
Granted, the cam had some overlap that bled off a bit of CR, but it had a fairly aggressive curve, 36 total, + vac advance.
I built my wedge that way. 9:1, 500 hp, 600 ft/lbs on 87 regular and more than enough bottom end torque to launch a 4800 lb New Yorker around with authority with 3.23 gears. 4.15 stroke.
He said it's a street car and it sounds like he drives it further than the local Dairy Queen. I'd build a 9:1 4.25 stroke tractor motor with a power brake friendly cam profile and enjoy the no drama able to drive it cross country street manners that can still roast tires or dust a 911 on a 60 mph roll on.
Kevin
