1968 Mercury Cougar GT-E 427/390 HP

[Rory McNeil]

Originally Posted by Billy Nees

Paul, they weren't "side-oilers" they were hydraulic lifter motors.

Actually, they were both. The "side oiler" designation refers to how the crankshaft recieved its oil pressure. The older top oiler 427s used a similar oil gallery routing like the 390-428s,where the crank recieved oil after the cam and lifters, the side oiler block has an external bulge down the drivers side of the block, which contains an oil passage that feeds the crank first. Also the earlier 427 blocks were solid lifter, with no passages to feed the lifters (FEs feed the rocker shafts via passages from #2&4 cam bearings, up thru the block and heads, to the shafts). Starting with the 68 Cougar GTE, and subsequent service blocks, the oil passages for hydraulic lifters were drilled.I have a 427 FE in my bracket Fairmont, with a 1971 service block, which is both a side oiler, and drilled for hydraulic lifters.