I have a small block 400 ci motor that has been align honed. When I put the new timing chain on it had a lot of slack. I call cloyes and they had me measure the cam to crank centerline. I came up with a measurement of 4.46 and it supposed to be 4.521. They sell undersize chains that are .005, .010, and .015. I know that will help but that still leaves some slop and I don't want that in this race engine. Will a gear drive setup work and will I have to special order a setup that won't be to tight?

An align hone should not even remove 0.005" I would expect..
The difference you have is 0.061". How did you measure it? I don't think your measurement is accurate.

I bought a Rollmaster timing set for an align honed big block and it was only 0.001" from memory.

Are you sure of the block's history?

I would go the .005 also.

I went to the cloyes site and measured it like it says on there page. You measure the crank diameter and the cam diameter. Devide both by two and add them together. Measure the space between the cam and the crank and add that to the number you have. That will give you your center distance. The info is in there high performance catolog.
I found a better solution to my problem with a dual gear drive set. They allow .070 to .005 amount of play. It was tight but the idle gear is now at .005 and my timing stays true.