**Note: If your hydraulic lifter preload is excessive, this can be easily remedied by using Crane's rocker arm pedestal shim kit 270-99170-1. Crane offers a pushrod guideplate and rocker arm stud conversion kit 270-52655-16 for street applications, enabling the 351C-351M-400ci engines with pedestal mounted rockers to have adjustable rocker arms without cylinder head removal or maching. To provide the most accurate valve adjustment on hydraulic lifter camshafts, the heads must be machined to accept 270-99159-16 screw-in studs and 270-52650-1 pushrod guideplates. On engines with cylinder heads equipped with exhaust valve rotators, valve springs and retainers must be changed to allow for proper valve travel.

***Note: Many problems can occur if the proper valve spring retainers are not used on 351C-351M and 400ci engines. Ford made a number of production changes in these engines, possibly causing a misapplication of parts. Please refer to the following explanation to insure that the proper components are being used.

• 1970-77 351C-351M-400 engines: Both intake and exhaust valves use multiple groove valve stem locks, with a large outside diameter, requiring the use of 3/8' type valve spring retainers.
• 1978 351M-400 Engines: The intake valves use multiple groove valve stem locks, requiring the use of 3/8' type valve spring retainers. The exhaust valves use standard single-groove valve stem locks, requiring the use of 11/32' valve spring retainers.
• 1979-82 351M-400 Engines: Both intake and exhaust valves use single-groove valve stem locks, requiring the use of 11/32' valve spring retainers.
• 1971-72 BOSS 351 Engines: Both intake and exhaust valves use single-groove valve stem locks, requiring the use of 11/32' valve spring retainers.

GOOD TO FAIR IDLE, DAILY USAGE, GOOD MID-RANGE TORQUE AND HP, MILD BRACKET RACING, AUTO TRANS W/2500+ CONVERTER, 2700-3200 CRUISE RPM, 9.5 TO 10.75 COMPRESSION RATIO ADVISED.