Everyone I've spoken with agree. There won't be any noticeable difference. Just make sure my tire won't come up and contact it.
I will be cheating the spring in a little to help them be more vertical, but I am guessing I'll only gain 5 deg or so.
I failed to get a picture, but here is where the drivers side was after welding it in solid:

Both sides are now in solid and everything is painted. I've made some straps to hold the spring in place similar to OE, and once the new springs arrive, I will build some stops so the spring can't go anywhere. Then it should be mounting it all up for the final time and see if I can flex it out somehow.
I will say it was easier than I expected to get all the stock stuff off the frame. I didn't clean it all off as some of it was left to keep the thickness for strength. But in the 10hrs +/- I have into it, I figured to be about half-way to where I am. Very pleased to know that maybe 2 more hours and I'll be testing it. Perhaps minor gains, but this gives me flexibility in the future and I know I won't miss those stiff 3.5" springs!
1973 Bronco, 351 SEFI, Locked, discs, 35's ZF-5spd and Atlas 4spd. 235:1 Crawl Ratio. It may be ugly, but it's slow.
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