Old style LA water pump or new style water pump With A/C

[Bronze Barracuda]

So there is a lot of information all over about the different style water pumps that came on the LA blocks. From what I've gathered if you have a pre 1970 LA block the timing cover is different (either a bolt on tab or cast into timing cover on passenger side) and the water pump is different (inlet is on the driver side).
It seems easy enough to find the regular type of water pump for pre 1970 but finding an A/C style pump is more difficult and when found the price is just about as heavy as the fact that it is cast iron. But even if we find or have the correct pump we may still need to locate the proper timing cover (cast timing marks or a bolt on tab). As well the radiator needs to match all of the above, with the outlet spout on the passenger side, or vice versa depending on what side of 1970 you are on.

First off I suppose all this only matters if you are running A/C on your car. Was the timing mark moved because the radiator was changed or was the A/C located differently, making it more difficult to read the timing marks. Is anyone using a later model timing cover with the older style water pump and radiator, if so how difficult is it to read the timing, easy hard, impossible? Also is anyone using a non A/C pump with a proper A/C pulley. Or better question is there a way to use a non A/C pump on an A/C car successfully?
Which brings me to another question regarding the flow of the A/C pump. I was visiting a local re-core shop and the guy said you can get new lines that are "dimpled" which slows the flow to allow the fluid to remain in the lines longer to further help with cooling, which kind of contradicts having a high volume/flow water pump. But I also read that the A/C pump has fewer blades which cause slower flow rates but at the same time have a smaller pulley which increases the speed of the pump to increase flow. (This is where my primitive brain starts to get dizzy) So my left side of my brain says to the right side, we will need a slower rate pump, but a faster rate pulley, with a slower flowing radiator if ya wanna run A/C? I need an aspirin.

So for all of us out there that are adding an aftermarket or sourcing an original A/C in to a pre 1970 car but no longer have the original engine or radiator (which is probably very common) or perhaps one or the other. What would be the least expensive way to go. Assuming they are not looking for the OEM look, just something to keep cool while driving a lone desert road at 100F.
My personal situation I have a radiator from 1968. 5 timing covers from 1970 and up and one timing cover from a 1965 273 with a missing timing tab. I will need a new water pump also. That is why I am curious if we can run a non A/C pump on a car with A/C somehow.
Or would it be best budget wise just to go with everything 1970+ rad, pump, pulley (was there a difference in the A/C pulleys pre 1970), and timing cover.
Edit: When do we use a pump with 2 port holes on the top as opposed to the pumps that have one hole on top?

 

[Professor Fate]

So there is a lot of information all over about the different style water pumps that came on the LA blocks. From what I've gathered if you have a pre 1970 LA block the timing cover is different (either a bolt on tab or cast into timing cover on passenger side) and the water pump is different (inlet is on the driver side).
It seems easy enough to find the regular type of water pump for pre 1970 but finding an A/C style pump is more difficult and when found the price is just about as heavy as the fact that it is cast iron. But even if we find or have the correct pump we may still need to locate the proper timing cover (cast timing marks or a bolt on tab). As well the radiator needs to match all of the above, with the outlet spout on the passenger side, or vice versa depending on what side of 1970 you are on.

First off I suppose all this only matters if you are running A/C on your car. Was the timing mark moved because the radiator was changed or was the A/C located differently, making it more difficult to read the timing marks. Is anyone using a later model timing cover with the older style water pump and radiator, if so how difficult is it to read the timing, easy hard, impossible? Also is anyone using a non A/C pump with a proper A/C pulley. Or better question is there a way to use a non A/C pump on an A/C car successfully?
Which brings me to another question regarding the flow of the A/C pump. I was visiting a local re-core shop and the guy said you can get new lines that are "dimpled" which slows the flow to allow the fluid to remain in the lines longer to further help with cooling, which kind of contradicts having a high volume/flow water pump. But I also read that the A/C pump has fewer blades which cause slower flow rates but at the same time have a smaller pulley which increases the speed of the pump to increase flow. (This is where my primitive brain starts to get dizzy) So my left side of my brain says to the right side, we will need a slower rate pump, but a faster rate pulley, with a slower flowing radiator if ya wanna run A/C? I need an aspirin.

So for all of us out there that are adding an aftermarket or sourcing an original A/C in to a pre 1970 car but no longer have the original engine or radiator (which is probably very common) or perhaps one or the other. What would be the least expensive way to go. Assuming they are not looking for the OEM look, just something to keep cool while driving a lone desert road at 100F.
My personal situation I have a radiator from 1968. 5 timing covers from 1970 and up and one timing cover from a 1965 273 with a missing timing tab. I will need a new water pump also. That is why I am curious if we can run a non A/C pump on a car with A/C somehow.
Or would it be best budget wise just to go with everything 1970+ rad, pump, pulley (was there a difference in the A/C pulleys pre 1970), and timing cover.
Edit: When do we use a pump with 2 port holes on the top as opposed to the pumps that have one hole on top?

Slow down there, pilgrim... one thing at a time. I'll try to take this in order.
The timing marks changed when the pumps changed. Either timing cover will physically work with either water pump, it's just that a mismatched setup will have the timing scale obscured by the pump inlet. It has nothing to do with the air conditioning, it's mounted up top, somewhat centered.
As far as the necessity of an AC dedicated water pump, look at what Mopar did. Only factory AC equipped cars got them. Cars that got dealer-installed air used the standard pump, and added pulleys to the crank to drive the AC compressor. They would also install a fan shroud if the car didn't already have one. If Ma Mopar thought the standard water pump would suffice in this situation, who am I to argue? If you can't find an AC pump, don't lose too much sleep over it. Or go to Flowkooler and get one of their pumps.
What style pump to go with? The early iron pump is shorter, so in situations where radiator clearance can be an issue, I would go with that. If you have extra room, go with the later aluminum pump. Ultimately, go with the one you have the pulleys and accessory (alternator, power steering, AC) mounting brackets for, since each is unique to that style pump.
Lastly, if you want to run the early pump and don't have a timing tab, or are using a late timing cover, just make a tab. It's a bent piece of sheet metal held on by the 2 bottom water pump bolts- nothing exotic.
Just make sure the timing marks on your balancer are correct for whichever style timing cover you use.

 

[Oldmanmopar]

69 and earlier AC with iron pump and 70 and later AC with aluminum pump

 

[Bronze Barracuda]

So the later model uses a 3 groove crank pulley and the older style a 4 groove. Looks as though the pulley on the power steering pump would be different also.

 

[Bronze Barracuda]

Slow down there, pilgrim... one thing at a time. I'll try to take this in order.
The timing marks changed when the pumps changed. Either timing cover will physically work with either water pump, it's just that a mismatched setup will have the timing scale obscured by the pump inlet. It has nothing to do with the air conditioning, it's mounted up top, somewhat centered.
As far as the necessity of an AC dedicated water pump, look at what Mopar did. Only factory AC equipped cars got them. Cars that got dealer-installed air used the standard pump, and added pulleys to the crank to drive the AC compressor. They would also install a fan shroud if the car didn't already have one. If Ma Mopar thought the standard water pump would suffice in this situation, who am I to argue? If you can't find an AC pump, don't lose too much sleep over it. Or go to Flowkooler and get one of their pumps.
What style pump to go with? The early iron pump is shorter, so in situations where radiator clearance can be an issue, I would go with that. If you have extra room, go with the later aluminum pump. Ultimately, go with the one you have the pulleys and accessory (alternator, power steering, AC) mounting brackets for, since each is unique to that style pump.
Lastly, if you want to run the early pump and don't have a timing tab, or are using a late timing cover, just make a tab. It's a bent piece of sheet metal held on by the 2 bottom water pump bolts- nothing exotic.
Just make sure the timing marks on your balancer are correct for whichever style timing cover you use.

Thanks I did not think about the dealer installed A/C. This helps out a lot.
Many of the questions were out of curiosity as well as the technical aspect.

 

[Professor Fate]

So the later model uses a 3 groove crank pulley and the older style a 4 groove. Looks as though the pulley on the power steering pump would be different also.

Look closer. They both use 3 groove crank pulleys.
Early= 1 groove drives the AC and uses an idler and tensioner pulley for belt adjustment. 1 groove drives the (high mount) power steering, and uses the pump to adjust the belt. The last groove drives the water pump and alternator, with the alt. for belt adjustment.
Late= 1 groove drives the (low mount) power steering and water pump, with the ps pump providing adjustment. 2 grooves (double belt) drive the AC and alternator, with the alternator adjusting the belt.
The only time I have seen a 4th groove on the crank pulley is on late LAs when an air pump was added for emissions.
Note that all brackets and pulleys are different due to the different depths of the early vs late water pumps, and are not interchangeable.