Motor opionions

Thinking about putting a new motor together.What wuold you build,its a 3/8 mile high banked track. Big bore short stroke or Small bore big stroke, 360 ci limit 12.5 comp 500 2 bbl car weighs 2835  

302 cid FULLY PORTED HEADS 2.02 INTAKE 1.60 EXAUST 58CC
CHAMBERS

283 INTAKE LIFT 287 EXAUST LIFT BOTH SEAT TO SEAT 106
DEGREE LOB CENTER SOLID ROLLER LIFTER WITH REV KIT

EDELBROCK II INTAKE 500 CFM HOLLEY
SHOULD BE GOOD TO 7000 RPM ABOUT 580 HP 450FP TORQUE  

With the small carb rule you can already answer the question.. small bore with big stroke. The longer stroke will give more time to draw air/fuel into the cyl. Try to get as close to the 360 cid limit and choose your cam very wisely... that will make the biggest difference. Call cam manufacturers with you details and they can be very helpful.  
"Remember when sex was safe and racing was dangerous?"

You are on the right track, no 302's or small bore.  350 .060 over dart sportsman 2.05 in 1.60 ex the 12.5 comp is good but you need to do it with a flat top piston and angle mill the heads to save weight. Get the lightest rotating assembly you can afford. VDL 500 2bbl, Victor junior 2bbl intake, Engle 28/29 camshaft 1.6 rockers in and ex and MSD 8365 distributor.  No you wont make 500 hp and 450 ft lbs but it will be close, trust me  

I am currently building a similar engine for a .555 mile high bank. The main rules I have to deal with are 2bbl,362 cid, .550 lift, cast everything, no roller. I run all my builds through a computer dyno program. Ross is right on the flat tops, the light rotating assy, and many other things. My new setup will be a 4.020 bore and 3.5 (not 3.48). I have found some alum rods that can handle circle track use and some very light pistons. This allowed my crank to be cut down and balanced at a mere 27#! I have some awesome bowtie cast heads and I am using the lunati 550 lift rule cam. We are now allowed the torker II and I had my carb guy setup a nice 4412. With alot of little details as well my program predicted 605 hp! On the real dyno we found 612 hp!

As Ross said you need to do it with flat tops... but there are a few head companies that offer heads with 49 cc chambers to pull it off easier.  
"Remember when sex was safe and racing was dangerous?"

i would have that dyno checked that is very high for that motor, two many limitation in that motor , 4412, cam lift and the heads i would believe 412 horse, altthough the lite assem, will race like a higher horse motor, wwhich will result in quicker acceration not higher power. also look to lighten the rest of the drive train , lite motor does best when the rest of the parts are lite to get the most benefit
   iceracer45
hope i did not hurt your feeling  

Just remember races are won in the corners. Your engine just has to keep up not beat up. Ask around your competitors and see what they're running. Of course they wont tell you everything, but it may give you a good ballpark. We have always been underpowered because of $$$ but still manage to win races. Good luck!!