My builder says over 650 hp it's a good idea, at 750 Hp it' better idea,800 it's a requirement. I know he uses them on all of the 4.25 stroke builds he's done. My 408Ci (5.7 based) makes 725 hp and has a older set of Pro-Gram , which now are manufactured/sold by Billet Speed works.

Last edited by Ray408G3Hemi; 07/31/19 11:00 AM.

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