[soupman]

The O.A.L. of impeller is 4 1/4". The vane height is 1/2" high and they are 2" long. The vane is even(zero deck height) with pump housing on the outer edge, but tapers upward by 1/4" toward the center shaft. anything else we need?

[grandville455]

Ok remeasured ..my impeller is 4 1/4 in diameter from edge to edge..if you just measure the diameter of vanes they are 3 3/4", with vanes being 1/2 inch tall and 1 1/2 long and do not sit flush with pump housing, refer back to my one pic to see it...where does it end lol

[Malky]

Back on page 4 or 5 of this topic I posted the sizes of my stock, original, '73 455 11-bolt pump, and I quote: "The impeller is nicely cast with 8 well-shaped, properly designed vanes. It is 4.4" OD. The vanes are 0.70" high above back plate at the inlet and 0.50" high at the OD. The inlet tips of the vanes have exactly the same diameter as the inlet hole in the plate, which is 2.4" so the impeller eye matches the hole perfectly. The vane contour exactly matches the plate, i.e. the gap between the plate and the vanes is 0.06" at the inlet and it stayed 0.06" (I checked with clay) right out to the impeller OD. The impeller has 3 balancing holes in the back plate to balance thrust and reduce load on the bearings."
Also, the backing plate is exactly 1/2" above flat surface.
Malcolm

[george kujanski]

Malky, thanx for the reminder. I am going to summarize the specs we have seen in this thread since I obviously have forgotten the details over the last few weeks.

I should be able to do it this weekend and post the results.

Your information is key since yours is a stock item. Thanx again for the info.

George

[george kujanski]

Here is what I have compiled so far:

[428GTO70]

I finally recieved my new divider plate and sleeves from gmpartsdirect.com, man that was slow. But anyways i can now go out and tear into my 428 sometime this weekend, So I will try to add some input on this discussion also when I am finished. I got my new pump from autozone, The 16 dollar rebuilt one had the cast iron impellar and the brand new 26 dollar one had the stamped impellar, so of course I got the cast one. I Hope this works!

[grandville455]

could you take some measurments of your impeller and plate for us for comparison to others here
thanks

[george kujanski]

From what I see here, some items stand out:

On a 8 bolt pump, two cast vane heights exist, with the higher vane being the OEM design, as found out by OLDGOAT67. The smaller vanes leave way too much clearance to be effective.

On a 11 bolt pump, the one to get is the larger diameter impeller as specified by MALKY, who has a known OEM style pump. Soupman also has what appears to be the same OEM pump. 72Firechicken has both flavors of cast impeller on a 11 bolt, with the stamped impeller actually being BETTER than a smaller diameter cast.

Cardone seems to be a good supplier of rebuilt units and Delco and GMB have pumps similar to the OEM dimensions.

Stamped impellers are generally inferior.

I have no idea where the other variations of cast impellers come from or what they were used on.

I'll update the list as more results come in.

Anyone have other opinions or something I missed?

George

[KS circutguy]

I just ordered a Carter new pump for my 1970 400, It appears to have a small diameter cast impeller.
Should be here latter this week.
For testing I also ordered a new separator and sleeve set too.
However, I have never had overheating problems yet, and I'm currently running a small cast rebuilder napa pump.
A "Rodney Red" radiator in my 1980 Firebird.

Very interesting topic though.
Steve
http://photo.starblvd.net/zanko20

[Malky]

Thanks for two summaries, George. There is a ton of good info on this topic but it is getting hard sifting it out of 10!! pages.

But people should remember this subject is great for those who have tried everything to cure overheating with no luck until now, but there are all the obvious things to check first, like thermostat, fan clutch, plugged rad, collapsing lower hose, air leaking around rad, no fan shroud - all the stuff that is well covered in the numerous overheating topics.
Malcolm

[Bill H]

This is an 8 bolt pump I put in my 67 GTO last year, it's the cast high vane type and works great. It's hanging up because I painted the exterior side. It's a Cardone pump

[72firechicken]

I need to correct my prior statement as to having 2 different size cast impellers I was wrong, both of the cast impellers were very similar in size, my bad, one of them was still on the car when I made the post I should have waited until I had them side by side. My results from the change from a stamped impeller to a cast with some backing plate tweaking were about the same with the stamped impelller.

[PMDRACER]

Has anybody ever tried modifying the 8 bolt pump, plates, and timing cover to allow water to flow through both sides like the 11 bolt pump?
If I remember the timing cover correctly, it would not be that big a deal to modify it to accept another sleeve/seal, and then get the plate to seal to it. The only thing left would be to mill a pocket in the pump to allow coolant to go that direction.

Just rattling the cage to see who barks.

[6t7gto]

got my cardone rebuild sat. morn. took the pump off my blue 67 and couldn't believe the diffrence in the pumps. the one i took off had the stamped impeller. the clearance to the backing plate was almost 3/8 inch.put the backing plate on the cardone and the clearance was about 1/4 inch. tweaked the plate, installed it and the temp went to 200. pulled the thermostat and found a 195 degree. replaced with a 160. now everything is COOL. life is good.
david

[6t7gto]

rudy, flushed the CLR out of my red 67 sat. again. still traces of CLR. i have refilled and drained it about 6 times. one more time today should do it. i'll pick up a 160 thermostat today. i think i'll be okay now.
david

[grandville455]

I just wanted to add one thing...Is that I have the ralleye gauges in my grandville and the middle setting where you would think that GM wanted the cars to run at is 210!So who knows really...but to me thats too damn hot I have what I believe to be the original pump with a new super 160 stat and it doesnt go past that even racing yesterday and it was 76 degrees not real hot but a good test It will be interesting to se what happens after i change pumps with this new one in a month or so

[KS circutguy]

Just got my Carter Pump heres the pics.
New spacer plate too, it has .060-.080 clearance as is, is that close enough?
Steve

[KS circutguy]

Another with plate

[george kujanski]

Wow! That looks really nice! Looks like good vane size also. From members' reports, .060 should work well. Can you take some measurements of vane size, length, etc? How much for that pump, KS?

George

[kate`s67gto]

I gapped mine at .040 roughly or 1mm. Car runs too cool now but up here we have not had a hot day i would consider as of yet. Car runs 140 with 160 stat. and Rodney Red rad. I`m waiting till hot weather to hit before i decide if i need to go to a 180 stat. Then the truth will be known, on my car. I give you this from a thermometer reading from rad after a good run on hiway, and town driving guage is not accurate off by 20*. I have very good flow of coolant through rad now, didn`t before had stamped steel impeller and temps of 210 plus constantly in town on hiway was 180. Sorry for such a long post ,I`m just thrilled to have the opposite problem as of now.