John,
This site is mainly for 95-99 Rivieras. Someone here may know, but probably not. Head over to www.v8buick.com, join, and ask there. Someone will know. Best thing to do is get a copy of the 1963 Buick Chassis manual. They are cheap on E Bay.
http://www.ebay.com/itm/1963-Buick-Chassis-Service-Manual-/111566704955?pt=Motors_Manuals_Literature&hash=item19f9e4d13b&vxp=mtr
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98 Riviera SC3800 All stock except gutted air box.
1970 Buick GS455 Stage1, TSP built 470BBB, 602HP/589TQ
Best MPH, 116.06 MPH, Best ET, 11.54
https://www.youtube.com/watch?v=UHCda-t_Jls
https://www.youtube.com/watch?v=sfT2tEO4XcU