This may or may not be relevant but, on stock configuration (carb) I had installed the big "rubber" seal for the filler neck upside down causing a fuel leak when tank was more than half full. Sorry if that is a non-helpful "hail Mary". Chuck
I would contact Eaton and send them pictures and measurements. Someone at Eaton made a rather large mistake. As a side note, all 1965-1973 Mustangs had a bit of a "tail dragger" stance from the factory. Chuck
It looks way high to me. What springs are installed? is everything seated properly? A ROUGH rule of thumb is however much you reduce the vertical height of the spring, the car will be lowered twice as much. Chuck
The ones near the A pillar (rear) are easy. More or less press fit and secured with hex head sheet metal screws. The front ones require quite a bit of work as they go between the core support and the fender frame. I can't remember all the steps but, it was a real PITA because I was mad at myself...
This is why the pre-mixed costs more than the concentrate. https://goglycolpros.com/blogs/ask-the-pros/water-quality-matters-glycol-mix#:~:text=Dow%C2%AE%20Chemical%20Company%20recommends,used%20in%20heat%20transfer%20systems. Chuck
I have never worked on an 429 SCJ Holley. However it sounds like Holley or Ford got in a hurry to me. A change in the idle channel restrictor and/or idle air bleed would have cured the rich idle problem. Just my two cents. Chuck
Usually with a small thin flat screwdriver. Turn it in to shift later, out to shift sooner. However, the modulator engages a small diameter "pin". If it is not there it will never shift properly. The length is also within a narrow range on length. A very faded memory want to say about 1.625"...
Found this. https://semomustang.com/products/air-filter-element-fa-41-boss-302-429-428-cobra-jet-429-cj-scj-351-windsor-390gt
Seach using the other cars listed in the SEMO page. Chuck
+1 on using a shroud properly (Sheriff1). Use an IR thermometer pointed at and relatively close to the thermostat housing for a more accurate temp reading...