Single or double?
Are you going for long term solution or a lets get it running?
If its lets get it running, then get the correct spacer (and bracket if need be) for the alternator to line up for the exisiting engine. Someone posted the water pump pulley was for a 70 with A/C. You check diameters and position to see if that's right. If so, then double pulley should line up. Also check the crankshaft pulley. The pulleys need to be a set so the drive ratio for the water pump and alternator are matched. Assuming this all came with the engine, its probably all OK to get you going,
Then you can look at a longer term solution. A new square top like you posted can work. Its just going to be a little project. Make sure you can get fan shroud for it and be prepared to spend some time checking fan spacing and positioning. When you trial the install, crumple up some aluminum foil and close the hood gently. See if there is clearance or contact.
Square top clearence as modified
You can always go back to your short term solution while you work out this out. I had to send the 68/70 radiator back to Bob because it was too tall. Its part of the process - he wouldn't take payment until it fit.
And this is the 5 blade clutch fan with the bubble top.
Too close for my comfort. Thats why I went to the factory fan with the notches to clear the tank.
One more component about the cooling to think about - at least long term - is a recovery tank. These cars only had an overflow hose. if you want a recovery tank, or will be participating in an activity where a catch can is required, then develop a plan for that too. it looks like the horns on your 69 are in similar location to my 67. Not much room there, but you can make brackets that will fit a quart can or tank.
and for the bubble top a different tank was needed
(I'm not a fan of electric fans on these cars. They are a project of their own with thier own headaches. One of which is the electrical aspects.)
IIRC the snout is shorter. So it effects the pully alignment and fan position. That's not good or bad. its just the things that need to be figured out so the system works.
Are you going for long term solution or a lets get it running?
If its lets get it running, then get the correct spacer (and bracket if need be) for the alternator to line up for the exisiting engine. Someone posted the water pump pulley was for a 70 with A/C. You check diameters and position to see if that's right. If so, then double pulley should line up. Also check the crankshaft pulley. The pulleys need to be a set so the drive ratio for the water pump and alternator are matched. Assuming this all came with the engine, its probably all OK to get you going,
Then you can look at a longer term solution. A new square top like you posted can work. Its just going to be a little project. Make sure you can get fan shroud for it and be prepared to spend some time checking fan spacing and positioning. When you trial the install, crumple up some aluminum foil and close the hood gently. See if there is clearance or contact.
Square top clearence as modified
You can always go back to your short term solution while you work out this out. I had to send the 68/70 radiator back to Bob because it was too tall. Its part of the process - he wouldn't take payment until it fit.
And this is the 5 blade clutch fan with the bubble top.
Too close for my comfort. Thats why I went to the factory fan with the notches to clear the tank.
One more component about the cooling to think about - at least long term - is a recovery tank. These cars only had an overflow hose. if you want a recovery tank, or will be participating in an activity where a catch can is required, then develop a plan for that too. it looks like the horns on your 69 are in similar location to my 67. Not much room there, but you can make brackets that will fit a quart can or tank.
and for the bubble top a different tank was needed
(I'm not a fan of electric fans on these cars. They are a project of their own with thier own headaches. One of which is the electrical aspects.)