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Old 12-17-2007, 01:03 PM
BogiesAnnex1 BogiesAnnex1 is offline
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Originally Posted by DARIN ALLMAN
Building a 1974 350 and bought a zz4 cam is there any way to make it work the back spacing on the cam gear is wrong and I'm stuck I've done bought my retro lifters roller rockers push rods cam button is there any thing I can do to make up the difference from not having a retainer plate or do I need to take out a loan to buy a retro roller cam thanks Darin
Yes, but first let me dump a little background.

The ZZ4 cam and all factory passenger car and some truck cams since 1987 are for the OEM roller config which uses block modifications; these being taller lifter blocks, cast and machined bosses on the main oil galley that mount an eight legged spider used to retain pair wise sets of bars that hold the roller lifters in alignment. The front of the block is modified to accept a cam retention plate that bolts on with 2 bolts to a pad added around the face of the front cam bearing. This requires a cam with a machined nose the thickness of the plate. The cam's timing gear hub is modified to accommodate the additional thickness of the plate and cam nose without moving it's position relative to the crank gear.

The solution on the front is to purchase the thrust plate and cut its ears off and to use the timing set for the OEM roller engine with a cam button to retain the roller cam.

But in the bigger scheme, while there are people who modify non roller blocks to roller use, it requires drilling and tapping into the main oil galley for spider retention bolts, this really isn't thick enough for the loads, and passing the bolt thru the oil galley would significantly reduce oil flow. The lifter blocks are also about 1/4 to 3/8s inch too short to adequately support OEM rollers. So I can't really recommend trying to put an OEM roller into a non-OEM roller block, just too many iffy compromises to suit me.

Now you could use aftermarket roller lifters but these are rather expensive. So by the time you do all this messing around, you might just as well pick up a roller block. For 350 roller tappet blocks look for casting numbers 10243880, 14011148, 14088526, and 14093638. The 880 is pretty common as it's the Vortec truck block.

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