the 08 was a 5.7, as for the A833 Vs the 727, I can't honestly answer that , the 76 she has now has been in the family since new and it was a 400 4 speed (NP435) ,my oldest daughter raced the truck 1st and that's when it swapped over to a 18 spline Box with a Long shifter HB 1000s .

I don't have any 727 experience ,My 74 D100 has an old Liberty Gear 18 spline behind the G2, . Both of my Lighting trucks use Rossler TH400.XHD in the 01 and a terminator 4 in the 93...Irony is I've never had a Ford auto behind any of my fords for more then a year...LOL

1963 Thunderbolt 496FE 10.80 (still a work in progress)
1968 Mustang slow a$$ 428 FE
1971 Boss 351 Mustang 11.20@115mph
1993 Lightning 10.61 @ 129mph 408Ci A3 headed NA
1996 Viper GTS
2001 Lightning 8.99 @ 155MPH 5.4 Mod Motor
2009 Ram 9.65@144MPH 463CI G3 NA
2010 Challenger 9.91 @ 139MPH 408CI G3ci NA
2019 F150 (local dealer's Lightning package) ..11.90s