ok, so I just went through different model years, and different engine options on the Eaton link from my post and cross referenced them to the GM part numbers.
It looks like this is what the Eaton application guide does:
(side)-(weight rating) = (GM part numner)/(Eaton part number); (application)
- RH-#89 = 482545/ML3661; 1970 & 1971 Firebird's w/350
- LH-#88 = 480878/ML1991; 1970 & 1971 Firebird's w/350
- RH-#103 = 482546/ML3595; 1970 & 1971 Firebird's w/400; 1972 & 1973 standard duty (both sides) w/350
- LH-#126 = 482548/ML231; 1970 & 1971 Firebird's w/400
- RH-#126 = 482547/ML559; 1970 & 1971 Trans Am's
- LH-#126 = 481612/ML1147; 1970 & 1971 Trans Am's; 1972 & 1973 heavy duty (both sides) w/350
- RH/LH-#126 = 481132/ML231; 1972 & 1973 standard duty w/400 & Trans Am
If I only focus on the differences for Formula an Trans Am models my MPC shows some small differences from the Eaton guide:
1) It shows that the 1973 Formula 400 & Formula 455 w/o Y99 used 'PR' 482548 as the service part for both sides, while the 1972 chart still shows in the same application used 482546/482548 just like 1970 & 1971 Formula's.
2) It shows that 1972 Y99 equipped Formula 350/400 cars and any car with a 455HO received 482547/481612.
3) It shows that 1973 Trans Am's & Y99 equipped Formulas used 'PJ' 481132 as OEM & SR parts for 1973.
So it looks to me like Bruce, you're suggesting I essentially opt for the 1973 'PJ' 481132 springs which are a number not used prior to 1973;
Wasn't the logic of different rate springs because this would aid in traction?
I'd like my car to launch like this when I get it done:
