I recently bought an engine my buddy pulled out of a 75 cutlass and we thought it was a 350. I got the casting number (395558   2). The big 2 in the casting number is the id code I think, and if so it says it is a 350 from 1968 to 1970. Then I pulled the vin number off the motor and it is 35M152400, 3 for olds, 5 for 1975, and M for michigan meaning the lansing plant. But when I was looking on 442.com it didnt have a listing for a 350 in 1975 only a 260 in which the casting numbers were the same but the id codes were different. I just wanted to know if I ran these numbers correct, cause im confused. Thank you for your help in advance  

The code you listed says that it is a 350 block that was produced from 1968 to 1976.  

The heads could've been swapped at some point int he car's life. The Olds 350 was a fair motor, basically designed to make torque to move their heavy cars. They were never really performance motors.

But, Edelbrock I believe has aluminum heads that fit those motors, and that's the biggest weakness is the poor flowing factory heads.  

Actually...thats not entirely correct.  The Olds big block was designed for low end torque.  The small block features a bigger bore and shorter stroke than the Chevy 350, and given that big block heads bolt right on...there are plenty of high performance cylinder head choices to use with them as well (Edelbrock, as you named, as well as Rocket Racing Performance and Mondello to name a couple more).  They'll spin up pretty high so long as you do the important (yet cheap) upgrades to the oiling system.  

Would you guys happen to know anywhere I could find the olds blue metallic engine paint?  

Year One has it for sure...I'm sure others have it as well (OPG for example).  You could also just find some metallic blue engine paint at your local parts store (which is what I did for the gold paint, original color, on my 350...as I did not care to have the exact correct shade of gold)