all this bigger is better talk around here has led me to wonder, why dont more people build 400s instead of 350s? i mean every time i pick up a hot rod magazine i see some story about 500HP 350s and the buildups. but i rarely see anyone do a buildup on a 400. i mean if 305 to 350 is such a big difference (and belive me, it is, my neck is still sore from being pressed into the headrest) then wouldnt 350 to 400 be an even greater difference. now granted, the heads/bore/stroke on a 305 greatly add to its lack of power and a 350 is a better motor to begin with, but still wouldnt an extra 50 cubes give some more ponies? just wondering......

 

Two words: "Block availability".

But there's more, and it is counter to your "305 vs 350 vs 400" argument.

Going from a 305 to a 355 is a 16.4% displacement increase. The change in piston area is a 16.3% increase.

Going from a 350 to a 406 is a 16% displacement increase. The change in piston area is only 6.3%.

The difference in breathing (evidenced by the change in piston area) from a 305 to a 355 is much greater than going from a 350 to a 406.

So, no, the change from a 350 to a 406 is not as big a jump as going from a 305 to a 355.

Having said all that, I wish I still had the 400 that was in the '70 Impala that I gave to my brother who gave it to his son who abandoned it in the streets of Topeka back in the mid-90's. Stock bore, stock crank, over a quarter million miles on it, still ran like it did with only 100k on it...

 

im building a 400 its been great 400's make big block torque and got small block weight, too bad there wernt more blocks available, but then i would have to worry about being slower more often

 

ya... availability... most of the junkyards have been picked clean by circle track racers and other racers.... i was lucky enough to find a rebuilt stock bore short block sitting on a stand in a building of parts my dad bought out (just bought some heads and a cam and induction and tossed em on and out cam LG4... less than 1500$ later i got a 400 small block with a little work done and vortec heads )

otherwise i prolly woulda gone the treefiddy route... ::

 

so why arent there that many 400s? was it a weak casting? or did they just not make many....

 

Cooling problems for 1, my friend had a 400 in his 80 camaro and had to run a 4 core radiator , full time dual electric fans, a low temp thermostat, and an edelbrocke pump to keep it cool and even then it still ran pretty freaken hot ,it wasnt stock but still I cant imagine what would make a motor run that hot, and another thing is 350's are just easier to come by and everyone knows how to work on them and what works well performence wise on them.If I had the money I would definetly go with a 406 though.