From Art's description of the points of interference, we can assume that the Hooker kit mounts the engine both lower and farther back than the OEM Monza mounts do. Which explains why so many people have had header and oil pan fitment issues trying to cross breed the two different types. And I also suspect that the other aftermarket mount kits from Trans Dapt, Hardy, etc., are all slightly different.
I've never built a V8 Vega for the street without the OEM pieces, so I have no first hand knowledge about dealing with the aftermarket stuff.
77 Vega Estate wagon- project(someday)will have TPI305/T-5, S-10 spindles/axles
72 Vega HB Drag Car -383/'Glide/9"(firstname.lastname@example.org)(email@example.com 1/8th)
76 Vega GT- 400/4spd/9" retired from active duty(rusty)
03 Silverado 2WD ex.cab (work truck/parts hauler)
04 Silverado 2WD ex.cab (retired)
06 Haulin' 20ft enclosed car transporter
93 Suburban- 350/4L60(retired)
00 Saturn SW2- wife's car
01 Saturn SC2- younger son's project
00 Saturn SL2- daughter's car
00 Saturn SL1- older son's ride
98 Saturn SW2- spare
and 3 more Saturn "parts cars"
Note- the very act of listing all of these has made me realize I have some kind of problem.....