broncbob

I don't really know, but my guess is velocity. I'm thinking the smaller opening is to speed up air flow, giving a slight over filling, or positive pressure VS static atmosphere pressure that the larger opening will give you. I may be way off though.

The shift forks will look cooked on the tips if they are bad. Best thing I can tell you is to have a friend turn the input while you shift the trans in the bottom half of the case on the bench and see what is going on.

You will have no problems with the front stock tires. I cant help much with paddle selection, as I have never been to silver lake. Get haulers and skip the molded paddles, they are heavy as hell and suck power.

I'm not quite sold on these yet, they sound like a 4 mill aggressive dune port for a ton more money. They sound more like a trail set up than a dune set up. I don't know about other duners, but I like a nice top end for the big hills and fast sections. It sounds like these will fail with out a bunch of porting work to put at least some top end in them. I had this very conversation with Kim and K&T when I built my 421, after I told him what I wanted he put me onto a ported cub, and I am very happy with it so far.

I sent him a offer 500 below NADA

3 ounces per gallon R50. It's what Kim form K&T suggests.

Mohawks and haulers or extremes, there is nothing else that comes close. Molded paddles are nothing more than heavy egg beaters for the sand. The suck worse than anything has sucked before. You will be better off on 3/4 dead haulers than any molded paddles.

I cooked 3rd gear to the shaft... I have seen pistons put on backwards, leak down tests failed from a lose primary drive gear, cylinder put on backwards, clutches installed in the wrong order, and a host of other stupid shit done when in a hurry.

Heat cycle it 3 times bliping the throttle, NEVER let it idle for more than 30 seconds. Re torque head, check jetting and let her rip! Do not up you oil mix, do not baby it past a jetting check. You may stop a bit more often to let it cool during the first tank of fuel, but make sure it hits operation temps before it stops. What your trying to so is make sure the rings don't glaze over, therefore never seating to the cylinder walls. This will cost you power and life of the rebuild.

I'm guessing that the 421 is going to kill my 371 aggressive dune port?

My bet is shift forks too if every thing is adjusted as it should be.

All gears or just a couple of them?

Thinking of stepping up from my 4 mill stock bore, aggresive dune port, to a clean up port cub. How much power increase should I see? I have been on a drag port cub, and it kills my stock bores, but never been on a clean up port.

Wait, the cans on the ends of my pipes are supposed to have shit in them?

I rock cut fronts, full rears, twin flags and a 6 over arm on my 4 mill. Don't think a 421 needs a wheelie bar? I have one stand my fat ass wayyyyyy up on a hard launch at Sand Mountain UT. No amount of clutch feathering was bring it back down either, I had to back out or go over. This is on a 8 over arm.