Valvetrain/Valve Lash Adjustment

[LEWISEMATKINJR]

'64-67 389 GTO had a flat tappet cam. The 389 engine was noted for serious valve train problems. Some genius at GM decided to save a few bucks and used pressed in rocker studs. The pressed in studs worked loose over time and detached from the head.

Dave

all Poncho's had valve train/timing chain problems on their engines. The 61-6 389 & 421 in standard 10.25 to 1 c.r. carried double valve springs from the factory. when you had to replace the t/c, you had to use an oem style morse chain unless you changed to double roller bicycle type chain & gears. i know because i grew up driving a '63 Bonneville Spt Cpe.