Here's what I came up with, rather lengthy but very informative. Love to hear any feedback.
I’m going to be running a sbc 400 in a modified (asphalt oval) this year and we are limited to 406 cubic inch, naturally aspirated power plant.
The problem was, that if I spent oodles on my block to make sure it has the power and endurance I would need, it would soon be no good to me, or I’d be illegal because after refreshening the block beyond .30 over, I’d be over the 406 cubic inches that we are restricted to. So, this is what I came up with:
I figured that I could de-stroke the sbc 400 and stay under the 406 cubic inches.
HERE’S WHAT I DID (with excellent results);
On my primary engine, it needed to be bored .40 over, splayed 4 bolt mains added (was a 2 bolt), decked for cleanup only.
-Callies Compstar balanced, 3.625 stroke crank
-6” Manley rods, rated for 200,000 lbs
-Ross 9cc dome pistons w/1.196 deck height
-Comp Cams roller lifters, roller rockers roller cam;
12-940-9, circle track, Gross valve lift 0.645 0.63, duration @ 0.02 Tappet lift 290 300, Valve timing @ 0.05 Int 24open 56closed, exh 58open 26closed, lobe lift 0.43 0.42, lobe sep 106
-Comp Cams valve springs, 943-16 @551 lbs operating
-Dart ported heads (to match intake) 58cc chambers, 220 runners, 208 int., 160 exh. With Manley stainless high endurance valves
-Edelbrock ported Super Victor intake
-Holley 850 DP (76 jets)
-Regular race parts such as High volume oil pump, stud girdles, headers, high volume fuel pump, water pump, etc.
RESULTS;
Dyno results;
593 HP @ 7,000 rpm, 38 degree timing. Engine dynoed to 7,500 rpm 586hp, BSFC .44
This “de-stroked” 400 is now a 395 cubic inch with 13.5:1
You can watch the 7,500 rpm dyno pull on u tube:
http://www.youtube.com/watch?v=i57Do3_x3Hs