Raw Water Pump questions

So my 68 Mustang has always had some minor cooling issues. Shortly after buying the boat I noticed the only time my temp started to climb was when I was just cruising the lake at idle speed. It became obvious that my boat liked having some water forced into the front facing angled raw water inlet. This issue got slightly worse once I added a Sherwood sea strainer and associated plumbing (taxing the raw water pump even more).
Since I like skiing more than driving, I've had to ask others to drive my boat and have always said "watch the temp gauge like a hawk" and if it starts to climb, shut it down. Of course novice drivers don't always do this and the boat was overheated a few times in the last 10 years (always cooled back down slowly without pumping cold lake water into a hot motor).   
Last season I finally broke down and did a head gasket, head work (machining, new valves & springs) and everything that goes with it (new block circulation pump/hoses/intake and exhaust gaskets/etc.). Towards the end of the season I had a couple more instances of the temp starting to climb when going slow. With all the time and $ recently put into Big Jim I want my cooling to be completely stable. This leads right back to my raw water pump. Since the beginning my Interceptor marinized 302 Ford V8 has always been a tricky one to get the right parts for (even for SKIDIM). From what I know none of the new raw water pumps sold fit my boat including SKIDIM Item# 0601 (looks quite different than mine). I'd like to replace the raw water pump with something that flows more, but don't want to start a major engineering project to do it. If any of you have experience with/know about water pump compatibility with late 60's Mustangs I'd love to hear from you. I'll include some pics of my setup so you can see what I'm dealing with.

I should also note I've never been able to remove the last section of hose before the pump, put it into a bucket of coolant and winterize this way. This should speak to the weakness of the pump or its air sucking tendencies.

Thanks Poobah. What this tells me is I need to rebuilt it, as it doesn't even have the suction to pull coolant into the motor with the short little section of hose you see going into the bucket (last pic). I can guarantee you the hose clamps were all triple checked as well. I noticed a decade ago that the shaft was slightly bent and the brass backing plate wasn't in the best shape. This tells me the air issue is with the pump itself.

Definitely don't have the in and outs switched, so I'll get started on a rebuild.

Got this info about a rebuild.

http://www.sherwoodpumps.com/en-us/Products/Engine+Cooling+Pumps/Crusader/P10700G_Detail/Literature.htm

Engine Cooling Pumps : Crusader : P10700G

Applications:
Interceptor
Pleasurecraft

P10700G
Engine Model: Interceptor

Engine Part Number:

Pump Availability: Obsolete

Sherwood Replacement Pump: N/A

Impeller Kit: 09959K

Minor Repair Kit: None Available

Major Repair Kit: 12252

Inlet Port: 3/4" NPT

Outlet Port: 3/4" NPT

You'll have to excuse Pete, his Motorola Tracfone from 1997 can't access the internet, so he's probably never visited the mobile version of this site... So he's likely unaware that it doesn't support some of the features of the full site (like links and photo uploads).

It's unfair to give people a hard time about not posting "proper" links when there's a good chance that the version of the site they're using doesn't allow them to. No one can upload pictures or create hyperlinks from the mobile version of this website unless you know how to code the HTML in your post. The buttons that support those features on te full site don't work on the mobile one.

I'm not sure you even realize that a mobile version of this site exists, let alone it's shortcomings- but the fact remains that a lot of people use it. So youre excused.

I had my pad for about a year and it still confuses me.Should take a class. In the fall I only took it to Florida and was kinda lost,mostly with pictures. So if I have to post a link or a picture I get out the laptop otherwise it's the pad or phone

Thanks everybody (even those ripping me for a bad link which works fine if you C & P it into your browser BTW).

That one section of hose is old, but it works fine, is air tight and I cut a replacement section a couple years ago that I keep on the boat just in case.

Here's the latest. Spoke with David at Depco Pump in FL yesterday and he sounded very knowledgeable. Only issue using them for a rebuild is cost. For some reason he quoted $282 for the rebuild kit, $209 for a new shaft (which it now looks like I don't need) and something like $60 for labor. Add round trip shipping from MN to this and I'm looking at over $600 to make this happen. On a bright note Marine Parts Source sells the major rebuild kit (the only one available) for $117 and since "major" doesn't look all that major (3 parts other than the impeller and gasket) I think I'll do it myself.

Not sure about my stat. I do know it's not something I've replaced and I've replaced a lot.

If you end up taking it apart that far you might as well change the bearings too. You can get the numbers off them and go to a local bearing supply. You could save yourself some money by not changing that impeller so often,cannot even tell you the last time I even had mine out. Every year is real overkill.

Got a part number and vendor for the seal kit?

The part number is in the photo above. Call David, 910-247-6201, he order it for me several years ago.

That's the most failed impellers I've ever heard of, yikes.

Like Gary I can get several years and hundreds of hours of enjoyment out of one.

I've ruined one impeller but the blades were perfect. Splashed the boat last spring with a totally dry block and the brass spun loose of the rubber.

Thanks Gary. Looks like exactly what I need.

Well took another look at it today and nothing, the water pump sounded good. Took it apart to install the new impeller and everything was solid, no slack, nothing loose. I already ordered the parts and will just monitor it. What gives? Have a good one. Looks like Sunday will be the day the boat gets dropped in.