8770 lists for n/a motors and certain turbo starions (I believe non intercooler models up till 87???) and the 9116 is something like 87-89 starions. The previous trend on starquest club was to run a 9116 on any 2.6, even n/a. Now the trend and consensus shifted to the 8770 in everything even motors boosting to 20+ psi. One gasket is thin and hard while the other is thick and soft, but when bolted down its the same thickness. Flip a coin, Ive read everything I could find and just got no where.

88 Montero, StarQuest turbo, Kormex 5speed +tuff-pan w/phoenix f. stage2 clutch, 4in lift+33' tires, 4.875 lsd, short-throw shifter, Aisin hubs, SR big brakes, gen2 uca's, elantra alt, and so much more... 16g turbo w/hardpipes + 4.90 locking disk-brake axle soon (maybe lsd or aussie front??)