Internal or external balance 406 sb???
 

I am looking at going from a 350 to a 400. Lost the 350 to rod bearing failure, and rod journal on crank. I know I can swap alot of my parts to the 400, I was at aprox. 475 hp with the 350. With a 406 making aprox. that much hp or more,not mention the increase in TQ. Will the stock 400 crank and rods handle it? I was looking at getting a crank kit, cast crank, and I beam rods. Should I get an internal ballanced kit? This is a street car and will not see much track time. The 400 I can get is a two bolt main block. Any other imput,help,or advice will be greatly appreciated.Thanks

Getting the crank kit is the way to go and internal balance too.
The 2-bolt block is fine. When I built my 379 the shop I took it to asked..
"Why not go 406..you are giving away 50 Lbs of torque right off"
I said RPM's with my parts would Kill the 406 and of course he said not if it's built right... So after a few years and some better parts I am going to a 422ci.. :)

The 2-bolt block is the way to go if using a stock 400 block. I'd go with the 350 5.7" rod if using stock rods. If you're planning on using a stock 400 crank, I'd external balance it because it'll cost a bunch to internal balance due to the addition of mallory metal. I ran a 406 with a stock block, stock cast crank and stock 350 rods w/arp bolts with 13:1 compression and a little solid flat tappet cam, World iron sportsman heads for years in a 3000 lb 63 Nova and never had a problem with the rotating asm. It ran 11.20's at 118 mph in Colorado in 8000 ft air.....

My dad ran 9.59 best with a factory 4 bolt block and a stock reground crank, in my dragster an 8.59 best. IMO factory cranks are better than the China cast crap most are selling now. External is fine for a factory crank, don't use a Fluidamper with it. If you are buying new, Callies has some inexpensive steel cranks and are worth paying the difference for. Their machine work is excellent. While it can be done, going more than 3.75 stroke is a pain without a raised cam block. Also the factory 400 rods are fine with ARP bolts, resized and magnifluxed. Ran as fast as 10.90's and never broke one. For your app the factory stuff will work fine.

Hey thanks guys, I am not used to messing with a 400. As far as this being a street engine, with a lower RPM range, looks like I should be able to get the engine up and running a lot cheaper than I thought, just get a rebuild kit with good pistons and have the rotating assembly balanced. THANKS for your help