Use paint stir sticks under the radiator to create a gap between the tank and core support and Play-Doh to check clearance to the cap. I ended up not using factory holes to get it where I wanted. I drilled the core support as well as the radiator mounting flange to arrange the mounting points. You will need some strip aluminum to build the flanges for mounting the fan shroud unit if you are using the Ford fans. I used 2" because it was there but had to trim it in a couple spots, might be better off with 1".
Mine sits 3/8" high from top of core support to corners of the tank and top of the cap is 1-1/2" high. The inside edge the core support is the limit of clearance. Mine rests tight on that inner edge so I used adhesive foam squares I got with my transmission cooler to stifle vibration.
If you are going electric, I recommend doing at least the ammeter bypass while you are at it, if not the bulkhead connector bypass, or at least make sure it's in good shape. If your fans run on a hot day, you could have issues pop up. I am currently in the process due to the ammeter heating up. I do also have an electric vacuum pump, but better safe than smoking.
Hope that helps.
