I discovered this afternoon that I have six parts engines that have hydraulic lifters, and three with adjustable lifters. It got me wondering what the differences would be in the engine I'm building. Would hydraulic lifters run better? less power? quieter? What would change in the engine besides lifters and rockers? Different cam? cam bearings? What about the head, it's from a solid rocker engine, different oiling? Sorry for all the questions, but I'm curious about whether to go hydraulic or adjustable. The engine is .030 over, 10/10 crank, balanced, some head work, 2bbl Clifford, stock exhaust manifold. Thanks, Charlie.

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Life is good!

I'm not sure to what degree you can mix and match hydraulic and non-hydraulic parts on a slant. I'm only responding since no-one else has yet.

What I do know is that when hydraulic lifters were added to the slant, it was done a little "backwards" to the way its done in a v8. In a v8, the lifters are fed high-pressure oil from the oil galleries- the lifters pass through the edge of the gallery and pick up oil thru an inlet hole in their sides.

On a slant, there IS no oil gallery passing adjacent to the lifters. Rather than re-designing the block to include the gallery, the hydraulic lifters get their oil "reverse Ford/Chevy style." The oil comes from the rocker arm shaft- the rockers feed oil into the top of hollow pushrods, and thence the oil flows down the pushrods to the lifters. Weird, but it works just fine.

What I'm not certain of is whether a slant head originally installed on a solid-lifter engine has enough oil feed volume to the rocker shaft to handle hydraulic rockers. My first guess is "yes," but OTOH there may have been an increase in the feed hole size to allow the added oil flow- that's still easier than re-casting the block.

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Hydrolic cams have a full groove on the cam for the oil feed to the top end. This should provide plenty of extra oil without the need for modifications to the head. Solid lifter cams don't have the groove and send less oil up to the rocker arms. You MUST be sure to use the proper rocker arms and push rods for the hydrolic system to work.

I can't say exactly that there is anything wrong with the hydrolic system, but I've always been fond of the classic sound of a solid liftered slant six. I wouldn't have it any other way.

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1980 Aspen 225 super six