Hello Everyone,

I am helping my dad clean up and paint a 400 motor, out of my '70 Dodge Challenger (not an original motor, I know the 400's didn't come in a '70), and have a question:  Will 440 stock heads fit a 400 block?  And, if so, how will they make a difference in performance, as to 400 stock heads?  I was told that a 400 (stock) has a quicker take off, as to a 440 (stock), but that the 440 will catch up, after take off, and eventually beat the 400.

We do have a couple 440 motors (that need rebuilding that is), but my 400 runs so good, and was just rebuilt recently, that I don't want to replace the 400 block.  So that is why I am thinking of just converting my motor into a 440 with 440 heads, since the heads do define the type of motor, right? 

Now, later on down the road, I may just replace the 400 block with a 440 one, but that will wait until I save up some more money to get the 440 block rebuilt, since I am currently restoring a 1969 Charger. 

Anyway, I'd love to read your input on what would be best- your opinions, would be greatly appreciated!

Thank you!

Priscilla

You need to check the casting numbers on the heads. Your 400 will have the same heads as a 440 if they are the same year. You also need to check and see if your pistons come all the way to the top of the block deck if so you need to use open chamber heads like the ones on your 400. I have a 400 and two 440s. One of the 440s is in a pick up and the other is in need of a rebuild. The 400 Im making a 500" stroker with. There are alot of cool things you can do with both the 400 and 440 engines that will make the bow tie boys and blue oval guys cry!!! 

sorry to tell you but putting the 440 heads on your 400 will not make it a 440. the bore size and stroke of the engine determines the size of the engine. the size and type of the chambers on the heads (closed or open )tech.can change the displacement of a engine but not noticable any differance. it determans the compresion mostly. the 440 heads will bolt up the same but there would be no gain unless they were a better casting or port design.