I need some help determining if I can run B1 MC heads on a factory 440 block with a 4.375 or less bore (currently 4.350). Other than shrouding, any issues with interference with the 2.4 Int valves?
Thanks

Not really what your asking but those heads will flow way beyond what a stock block will handle hp wise. And at 500" you'll have to turn the piss out of it

Stock block required for the class. I plan billet aluminum caps and a girdle to shore up the bottom end, wanting to get 900 or so out of it. Just need to know if the 2.4" intake valves will work in a 4.350 bore AND if they'll be worse than smaller valves for a 500" bullet. I am buying used heads if they'll work, thanks.

Dude, buy yourself a good 400 block to start with, no amount of bandaids are going to fix that stock 440 block main webbing I've seen 440 blocks break and crack the main webbing between the cylinders at 700 HP with good parts

Cab,
It's a rule in his class to have an original block for the year car he is racing. Any idea if a 4.350 bore will fit a 2.400 intake valve?

No idea at all, sorry.

Should clear fine...........if it won't, notch the bore. Not the first time that's had to be done. And with the right cam, you WON'T have to spin it to the moon to make it run.

As for stock block rule.........tell em its a 383 car.......LOL!!!

I can use any factory block size that was available in the car. It doesn't have to be the correct year, but I can't use a 400 or 360 block for instance in a 1969 car.
Thanks for the replies.

A grinder and JB weld makes "383" numbers on the side of the block rather easily if anyone gets nosy..

Call Koffels. Just testing by hand I've had 2.30 valves hit a 4.375 bore at .680" lift in factory iron heads. Original B1 have the valves moved a small amount, don't know about the B1 MC heads.

Thanks Jim

Good point!

Consider a center weighted crank. It greatly reduces the stress shifted to the inner bearings because the counter weights are more in line with the forces they are offsetting. I saw the cap walk go away in a Megablock I have when I went to a center weighted crank, and the bob weight is 2432, pretty heavy. The cost difference is around 2500 for a crower, been a long time since I bought mine so it may be higher, but worth every dime for a project like yours. If you can use a 400 block, and lighten the rotating assembly as much as possible, the deal might live a decent life.

Thanks Greg

The center counter weighted crankshaft makes good sense. I wasn't thinking about that this morning, but have heard a lot people say what Greg just did.

Have you considered doing Darton sleeves? I know in a normal build it doesn't make sense but for a stock block class that you're obviously set on kill for it might make sense. Btw, there have been legit reports of 383's using 400 castings when the crossover was happening........I think for warranty blocks they used 400 castings. A 400 with Darton sleeves would get it done

I'm unfamiliar with the term "center weighted crank".

Can someone please explain?

Good stuff, thanks fellas, keep it coming!

Center counter weighted. Notice all of the counterweights are the same size.

That sure is pretty Polished and lightweight, maybe not a ultra lightweight, but lighter than ones I've weighed Tom, how long is the stroke on this one?