Absolutely nothing odd about running 40 degrees of timing for best results. Known of a few combinations over the years( smallblocks) that was the case. One was a stroker B1BA headed motor that immediately comes to mind.
Few years back i had a ross flattop 416 Hensley built i had eddies on top of. Sold the whole top end. Ran that combo several years, liked 34 degrees best( and i tried it everywhere)
Put W5 heads on that shortblock, TTi W 5 headers, a modified Victor W2 i bought from Brett, and plopped all that stuff on the untouched 416.
Had the timing all over the place on that motor, and the car flat ran a tenth better at 40 degrees than it did at 36, 34 or 32.... the other places i ran it..... late that same year i broke that cast crank 416 shortblock.
Built a new roller x block 422 with CP domes. Dropped the W5 topend on that, and it was happiest at 32.......... slower everywhere else