I ran an 8 1/4 in the 73 Scamp (my avatar) that I had for many years. Aftermarket 3.90 gears with an Auburn cone type sure grip. Factory axles. Factory cover. No bracing or anything. Car was not lightened at all.
It had multiple engine combinations. One was a mild 360 with a 100 shot of nitrous. 235/60/15 Mickey Thompson drag radials at the strip. Best time was in the 12.2s if memory serves. Lots of passes on that combo. Also ran a hotter 360 with better heads and no nitrous with the drag radials. I think that combo ran very low 13s. Never had a single problem with it. I sold the car to a guy I know several years ago and it's still going strong (he rarely races it - mostly street driven).
Your truck is obviously heavier than my Scamp so that is an additional factor. But overall I was very impressed with the 8 1/4.