How I put a 1975 Radiator in my 1972. These are $141.99 at O'Reilly Auto Parts here in Cali. But I got it with 20% off that price with their special they had.

Good job, and avoided the cutting and welding that others (myself included) have done. 
IF..., you have any cooling issues I recommend the following:

1. Reinstall the lower shield. It might be necessary to have the proper air pressure under the car that allows hot air to be drawn out rather than trapped.

2. Similar to point #1 foam around the gaps will force outside air only to be drawn into the radiator.  On Sunbeam Tigers we have issues with the hot air recirculating out cradle openings and back through the radiator. In essence using hot air to try and cool a hot radiator.

3. Fan shrouds are helpful to getting the best air draw.

4.  Yes, the large radiator does sit on the valance. You might consider a thin piece of rubber both as a noise vibration shield and to prevent rubbing wear on the radiator.

1-3 may not be necessary, only time will tell. 4 is a recommendation .  I'm sure others will find this helpful. Glad to see you took on the challange and found solutions. You may want to change the title to reflect that it is about installing a larger radiator.