Nope ! My R/B water pump catalog shows 59 to 62 the same. Rebuilding is not hard if you have a press and a puller or 2. Bigger prob is getting the parts ,aftermarket W/P kits went out of fashion 40-50 years ago.
Yeah the 1963 water pump is different from a 59-62 water pump. A 1963 still has the 390 engine but it is different from 59-62. Remember there are two different kinds when ordering a waterpump with A/C and without A/C. I got mine from Kanter but paid a shitload plus charged for the core price. I've seen them on ebay a couple of times.
E-mail this guy. [email protected] He's from Troy, MI. He had one for my 57' 365 Caddy which is the only year for the lower outlet on the passenger side. I'm pretty confident he could help you out and he is a hell of a nice guy with a price alot better than Kanters. Or you can ask a good parts store the address to a H2O rebuilder and send it off seeing that part stores don't have a part # listed.
I looked into this a short while back for a customers '59 390 & Kanter in NJ came up cheapest by far! Kev.
Had this guy rebuild mine for $150 plus shipping. He installs impellers with more vanes and puts fresh bearings, seal, etc in it. Two week turnaround, just as he promised. http://www.howardstewartrestorations.com/index.html Gary
I found a place on the internet called Falcon Sales e-store and they advertise a 'new' water pump for a 1960 Caddy for $167. "1958-62 caddy 365 390 V-8 with or without AC. Brand new pump with improved seal, leak tested, complete with gaskets, and new brass fittings, ready to install." Anyone dealt with them before? (Kanter was $208)