Hi i have a 400 that im am working on doing some motor work to. i bought a comp cams magnum cam and i need to buy some pushrods but i don know what size i have to buy does anyone know what size they are

 

Here is a link that gives a Ford part #.

http://home.earthlink.net/~bubbaf250/parts/parts03.html

I think that I know the lenth, but I haven't been able to verify it anywhere, and I don't want to steer you wrong.

You should get an adjustable pushrod gauge and measure the length. If your heads or block has been machined, you will need a different length than stock.