We need RPM for a 3/8 track. Its so short on the straight, and the cars are very wild suspention wise. They are constantly on and off the throttle. Its never at full throttle for longer than a few seconds, but its the decel that is hard on them. They get tossed in the corners really hard, and use engine braking to make the cars handle. If you havent watched these cars in action DO, they are AWSOME to watch, and they are a handfull!!

Limited late models, or just a local latemodel race is hair raising.

dirt track is my favorite roundy round to watch, but i haven't been to one in years, but I didn't think the wissota cars I used to watch up in Proctor or Superior spun that high.

I'd suggest talking to Jesse Lackman, I think he's had experience building dirt track motors, and I think Don (Moparsforlife) has friends who are heavy into the dirt track scene in N. Dakota....they might be able to give some advice.

what heads are allowed to be exact? aftermarket iron OK? I presume so since the W2's are class legal. for that kind of RPM I guess I'd be inclined to go short stroke/big bore to minimize valve shrouding and piston speed while maximizing displacement. a 383 with a crank destroked to 3.25" would net 369 CID, 374 CID at .030 over. add some indy SR's, and a small dome piston (~12cc) and you're in the 11.5:1 compression range.

with a 4.25" basic bore, you're looking at BBC standard bore sizes, so there's a ton of pistons out there that you might be able to adapt with some rework of the dome/valve pockets.

looking at the Kieth Black forged pistons for 454's, doing the math,

BBC pistons with a 1.27 comp height and 7.1" rods gets you .015 out of the hole

BBC pistons with a 1.52" comp height and 6.8" rods gets you .035 in the hole

BBC pistons with a 1.645 comp height, couple that with some BBC 6.7" rods and a 3.25" stroke, and you're looking at a piston sitting .010 in the hole.

granted main and rod journals (assuming using shelf 2.2" journal BBC rods) are bigger than an LA, but mains are smaller than a 360....

bummer things are so restrictive. I guess I'd use a .020 340 block, personally, or start scouting for a poly block with thick walls to bore out to 4.00 or 4.03.... then you could use KB107's and stock length rods with the 3.58" crank.

FWIW, a 3.58" crank, and 6" rods needs a 1.81" CH piston for 0 deck...which is the compression height of a KB167, or a KB 165 (chev 283 app, 3.875" bore, available .060 over, which would be a .025" over 318 bore)

KB165's are 488g/145g piston/pin, 167's are 507/132 (odd to me that the larger pin is lighter)

I would use these rods:

http://www.competitionproducts.com/prodinfo.asp?number=CPXPPF6000

that's for a set of 8....killer price, killer rod.

but spinning it that high, I'd probably do as long a rod as possible, and look at a shelf 4" stroker piston and a 6.35" long rod...

The rods look awsome!!

Has any of you guys on here ever use a howards rod?? The guy I talked to said they are 100% US made, in house with us 4140 blanks.
He also told me the powdered metal rods are just as ductile as the 4140 billets. They arent brittle like the oem style powdered metal rods.

I don't want to rain on your parade---but I think I should!

You are wanting to build a 480HP/two barrel/flat tappet dirt engine. Getting the 480Hp isn't a problem---getting it to live is a problem. Your weak point is the connecting rods/crankshaft. Get the best you can possibly afford---billet rods are the best choice---forget about Eagle, CAT, etc. You need something like an Oliver, King, or Crower seems to work well in this type of application. Why do you need this level of component? The dirt track gets rough---the cars "hook" so well---the vibration will kill substandard components.

Frankly, with a limited budget I would use a 360 block---don't worry about the larger main bearing. Use main and head studs!

Go on over to Moparchat---look in the circle track section---read the "Typical Oiling Modifications". If you follow the instructions, it will keep you out of trouble. While you are at it---prepare two blocks! A good 360 block will be good for 2000 laps!

The W2 heads will be fine with a good valve pocket work, shorted the intake guides 1/2", and make a cutter to machine the valve pocket down to the guide. If rules allow, use 2.06" BBC intake valves(shortened), the standard W2 exhaust is fine. If you can, 11/32" stems is nice but not absolutely essential. Set up a .050" seat width on both I/E. Check your intake manifold very closely for intake port alignment---most intakes require some TIG welding to properly align with the cylinder head intake runners. The heads should flow about 250-260CFM if properly worked.

With the two barrel(500CFM) Holley, you will need a cam with about .600" lift (AT THE VALVE), about 250 degrees @.050"(Intake), about 252 degrees (EXHAUST). Use a lobe separation of 108 degrees. Set the cam in at 104 degrees.

Use exhaust headers with 1 7/8" primary tubes/2" secondary/3 1/2" collector.

Use an MSD ignition, 32 degrees (Locked), 6AL box will be OK.

Buiding a good SB Mopar for limited late model is fun---just remember those chassis/tires are very hard on components.

I honestly think your budget needs to be at least $6K---with you doing all the engine work---and that's tight!

Good Luck!