I am building a mostly street driven 493 stroker with aprox. 600hp. After checking the rods I have
(4 rods) .0026 clearance
(2 rods) .0027 clearance
(1 rod) .0029 clearance
(1 rod) .0033 clearance
My question is...... is .0026 too little clearance and is .0033 too much clearance?
Thanks for any help you can give me.

I think you will be fine.
Is the variation due to the grind on the journals, or the rod big end fit?

minimum you want to see would be .015-.017 sounds like you're fine.

more has never been a problem. too little and bad things happen.

Although, I'll admit, that much difference is puzzling. check the bearings to make sure they're not upside down on a rod or 2. if it's upside down/backwards, the bearing may ride on the chamfer of the crank and not let the rod go all the way over against the crank.

The Rods are within .0002. The difference is in the crank grind.

What are the mains? Is this crank .010 undersized or new?

New crank, I won't mention the name because I don't want to start a war. The mains are all .003".

I think you would be fine... It would be interesting to know what the reason is, though. I have no idea what brand of parts you are using, but the Chinese cranks all need to go to a competent crank grinder for inspection/correction. I had two here recently that could NEVER have been run out of the box. They were a mess. The Eagle cranks lately have been improved, but my feeling is that for the few extra $$ to get the crank truly dimensionally correct, its well worth it.

MB

I will tell you that this crank is about ten years old and never been used, so it can't be compared to the cranks they sell now.

I think you're safe.
However: do not start with high viscosity oil "just to be sure".