My first 400 block stroker motor made 612 HP at 5500 RPM and 644 Ft. lbs. torque at 4500 RPM, that was with 9.25 to 1 compression using a set of mildly ported 906 heads (flowed 266 at 28.0 inches at .700 lift on Pettis 600 Super flow bench) with 2.14 intake and 1.81 ex. valves. Comp Cams solid roller custom ground for Benschoff racing (SP?) in WI. the testing was done on Vrbansic Bros. (Ontario, CA) DTS engine dyno in 2003 or 2004, CRS We tested three different sets of six pack carbs and multiple air cleaners combination. the best results are posted where with the stock air cleaner base with no air cleaner and a set of the Holley mechanical carbs with stock jetting, the worst results where with a set of replacement Holley 1971 440 automatic carbs with stock jetting that bogged horribly when open but still made 605 HP at 5400 RPM
I put the motor in my Duster and took it to Woodburn drag strip in October of 2005 after we moved to Oregon, it ran a best of 10.69 at 124. MPH.
I swapped the heads that winter to a set of MCH CNC ported Eddy RPM heads that flowed 319 CFM at .700 on MCH flow bench and flowed 310 CFM on Pettis bench at .700 lift with 28 inches of water on his Super Flow bench Both sets of heads had 84 CC so the motor ended up having the same compression ratio and a different set of 1.6 rockers, I took the CAT 1.6 ratio rockers off(they where wearing the shafts out nmaking metal ) and put a set of Harland sharp 1.65 ratio on the Eddy heads, those two changes ended up making the car go 10.49 at 126 MPH
I ended up changing a lot of other things on the motor including the cranks shaft increasing the stroke .050 to make the same pistons and rods end up with 10.29 to 1 compression ratio and increased the C.I. from 511 to 517, that change made the car go 10.30s ET at 127.+ MPH
The last change was going to a set of Indy SR M.W. size ports not CNC ported with a Indy 400-3 intake with a Wilson manifold 1.5 inch reversion spacer with a 19x3.0 inch air cleaner instead of the stock type six pack air cleaner with two K&N six pack elements on it. I ended up using several different Holley 1050 CFM Dominator carbs on the motor that ended up with a best ET of 9.993 at 134.+ MPH through the 3.0 inch exhaust with the 16x3.0 inch tall paper air cleaner element on using 91 octane non ethanol pump swill, the car weighed 3450 Lbs. with me in it.
I had a lot of fun and learned a bunch from that car and different engine combinations I did try a set of 440-1 heads with 2.25 intake valves that where CNC ported by MCH, on the DTS engine dyno in Klamath Falls OR they made 50 HP more on my Duster motor with the same compression ratio, those heads flowed 30 CFM more at .700 (370 CFM)than the SR heads did on the same bench
I would of loved to try a set of B1 heads that flowed over 400 CFM with that short block making less than 11.0 to 1 compression
My message is results on the dyno compared to at the track may or may not make what you think it should, go test that motor Brad in the car