My last pump gas low deck stroker made 727 HP at 7000 RPM with around 675 Ft. lbs. around 5200 RPM on Oregon 91 octane pump swill with no Ethanol in Klamath Falls, OR which is right at 4300 Ft. above sea level on a DTS engine dyno.
The motor was a 400 block bored to 4.375 with a 4.300 stroke crankshaft which was 517 C.I. with right at 10.78 to 1 compression, it had a set of Indy SR heads with M.W. intake ports and a Indy 400-3 intake with a Holley List # 9375 non HP carb. with stock jetting The cam was a comp Cams solid roller lifter grind with 260@ .050 on the intake with .420 lobe lift and 266@.050 on the exhaust with .409 lobe lift , Harland Sharp 1.65 ratio single shaft roller rocker arms That makes it have 1.406 HP per C.I., not bad but not the best either
I had that motor in my old 1971 Duster that weighed 3450 Lbs. with me in it ready to race with full stock gas tank, it ran a best ever of 9.993 at 134.7 MPH at Woodburn, OR drag strip in August of 2008 or 2009, CRS, cork up full 3.0 inch diameter exhaust system to the rear bumper with the air cleaner on.
That motor and that car far exceeded my wildest dreams
I've thought of building another 1970/71 pump gas street Duster to see how much better I can make it run with what I learned from the last one
Probably not going to happen now though due to many other car projects in front of that desire