You might try USA Parts Supply--see
www.usapartssupply.com
Their prices are very competitive. I ordered several things for my 69 442 and they were very responsive. The parts arrived promptly and they handled things very well over the phone.
I ordered parts from some of the other suppliers and didn't have as much luck. Some things took a long time and the bronze engine paint from Year One turned out to be a dirty brown. They made it right by giving me credit on my account, but the paint was nowhere near the Olds bronze.
My engine guy just got done with a 455 rebuild. Can't wait to hear it fired up--bored .30 over, with a cam and Edelbrock carb. Isn't the rumble music to the ears.......
Fred H