I have a 68 that has benn cloned into a 400. The 400 has the old style 8 bolt waster pump. I pulled it due to rising water temp at idle and was checking out the plate-to-impeller clearance. Anyway, the bottom,or first plate is there, but the second piece is missing.Does anyone know what the purpose of the 2-piece design is? Also, I've noticed the 2 inserts that sre in the parts catalogs. Do those need to be there also? If so,where exactly do they go?

Those inserts are for the 11 bolt water pumps and go inbetween the divider plate and the timing cover where it feeds the block.
There should be a second plate on the 8 bolt pumps that goes in between the water pump and the divider plate that has the chamfers.My guess is it helps divert the coolant and helps to pump more effectively.
I just did a 8 bolt pump a few weeks ago with the after market stainless steel divider plates.
They do need some trimming and grinding to fit them in the timing cover properly.

Thanks for the info-that helps a lot! Does anyone have any experience with the Flow-Kooler water pumps? Are they worth the extra cost?

I picked up a flow kooler for my engine, well see how it works out in a few weeks, just when it hits 100+ here

Tried a flowkooler...no real difference from a properly set up original.

Has anyone tried a pump from Evans.

Interesting. I had the Flowkooler on backorder from Ames for like 3 weeks and cancelled it today since I saw it at summit. I did receive the new divider plates from Ames. So now I'm reading up on the cardone pumps and am curious if the flowkooler is worth it. I wonder if cardone with proper diverter plate clearance out "kools" the flow kooler with a proper diverter plate.

My 2 cents: Cardone with cast impellor with properly spaced divider plates is the way to go. I've tried both.

Wanna buy a slightly used FlowKooler?

I ordered a new Cardone pump and stainless divider plate set.I'll update on the installed results.

Good call. Those stainless plates may require a little fitting...which is a good thing. Mine literally snap into place after a bit of filing.

Ordered the cardone pump instead of the flow kooler last night. Summit only had them in stock in OH so they said they would overnight it for free. Awesome! Might invest the $100 I saved into some filler panel plates, since my original 326 didn't have them. Really hoping to get this stuck in traffic overheating issue fixed so I can move on to the other 900 things I need to work on. So I guess it'll be trimming and filing time on the divider this weekend. Do you guys just peen the edge of the diverter or do you make the whole thing as close to flush with the impellors?

I actually "massaged" the divider plate until it barely touched the impellor...more than just the edge. The gasket will add clearance upon installation.

It won't take much time to fit the plates. As mentioned, mine "snap" into place in the timing chain cover.