HEY,  CAN ANYONE TELL ME WHAT THIS MOTOR IS?  IS IT STRONG?  STRONGER AND MORE RELIABLE THAN THE 350?  AND WHATS A GOOD TRANS FOR IT.  ITS FOR A JEEP WRANGLER YJ AUTO. I HAVE A CHANCE TO BUY BOTH.  THANKS!!  

A 406 is a 400 SB bored .030 over with special pistons and 350 rods (rods and pistons are optional) My take on this is I shy away for 400 SB's in SUV's because the cylinders are Siamesed together because bore center do not allow for the 4.125 bores in SB and also have full water jackets. They are not engines that take kindly to overheating over best for working hard under extended heavy loads. Best route here is a 383 which is a 400 crank and rods in a 350 block. YOu turn 400 mains down to 350 size and use stock 350 pistons and also use 400SB damper and flywheel as 400 crank is externally balanced.  

The 406 is a good motor if it is properly cooled and not overheated. they make awsome like the 383 but for a fraction of the cost to build.  

Tyler__820:
The 406 is a good motor if it is properly cooled and not overheated. they make awsome like the 383 but for a fraction of the cost to build.

Not sure what you are saying here as a 383 is pretty cheap to build. Just need a used 400 crank and set of rods. Does not matter if crank needs turning because it has to be turned anyway.  

i would sooo rather build a 383 than a 406sb. like snoman said with the siamesed cylinders they are not a good plan. especially in a wheeler or for racing. i know several racers that went that route and came right back to the 383 formula. and heck, even if ya can't find a 400 crank,  stroker "kits" are dirt cheap now. man, you can build the snot out of a sb chevy for like $3.29...build a buick? ya better have ole Donny Trump fer a daddy.  

I will tell you a real bone yard sleeper if you can find one. A 1970 Caddy 500. That year it was rated at 400 HP and 550 ft lbs of torque!! As far as using it in a 4x4, as far as tranny and Tcase, you simply swap the tail shaft on its THM475 and install tall shaft a THM400 4x4.  

haha thats some real parts breakin power right there! another good motor in my opinion would be the olds 455, they will go and go all day long, you can over heat them, run em out of oil and they will still go. but i would recomend doing it just to test it. lol  

snoman, i knew a fella years ago who whacked off the top of a late 60's early 70's Cad hearse (ala ElCamino) and used it for haulin firewood up in Michigan. it was uglier than a zit on a titty but man it had that big 472 and it was a monster!  

For many years Cadillac made it a point to always have biggest motor available in a car. When I was in high school in late 60's a buddy of mines dad bought a cherry 58 caddy cheap from some estate sale with low mileage on it. It had a early THM400 in it and a high compression 4bbl V8 that required best pump fuel available then and that thing ran for a old lead sled and would easily smoke tires badly just stepping into it hard.  

i think my n14 550 will pull harder