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Keith Seymore · 01-29-2015, 03:39 PM

You didn't say what year or series, but I checked 1987 R20 JB7 vs JD7:

Pedal ratio is different between the two so the pedal itself is different.

Vacuum = 4.51:1

Hydraboost = 5.60:1

K

01-29-2015, 03:39 PM	#5
Keith Seymore Registered User Join Date: May 2009 Location: Motor City Posts: 9,285	Re: I heard a rumor You didn't say what year or series, but I checked 1987 R20 JB7 vs JD7: Pedal ratio is different between the two so the pedal itself is different. Vacuum = 4.51:1 Hydraboost = 5.60:1 K __________________ Chevrolet Flint Assembly 1979-1986 GM Full Size Truck Engineering 1986 - 2019 Intro from an Old Assembly Guy: http://67-72chevytrucks.com/vboard/s...d.php?t=342926 My Pontiac story: http://forums.maxperformanceinc.com/...d.php?t=560524 Chevelle intro: http://www.superchevy.com/features/s...hevy-chevelle/