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To answer your question, no, you would not add the preload distance for piston to valve clearance. To do both proceedures properly, you really need an adjustable roller lifter to go along with your adjustable push rod - so you can adjust the cup depth to include the preload distance. Then adjust the pushrod length to get the proper scrub pattern accross the valve stem. IMO, the most important thing is rocker to valve stem scrub pattern. Secondary is preload - as long as you are in the range of the lifters plunger travel.

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To answer your question, no, you would not add the preload distance for piston to valve clearance. To do both proceedures properly, you really need an adjustable roller lifter to go along with your adjustable push rod - so you can adjust the cup depth to include the preload distance. Then adjust the pushrod length to get the proper scrub pattern accross the valve stem. IMO, the most important thing is rocker to valve stem scrub pattern. Secondary is preload - as long as you are in the range of the lifters plunger travel.

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he's pretty limited on the scrub pattern with stock rockers, especially considering how they mount to the head.
i would include the preload in the overall measurement for piston to valve on that particular engine if it'll see higher than stock rpm.

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Why would you want to include preload - unless you are concerned about valve float? I assumed he went with valve springs that were applicable to the cam. It would be a safer way to go I suppose.

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To answer your question, no, you would not add the preload distance for piston to valve clearance. To do both proceedures properly, you really need an adjustable roller lifter to go along with your adjustable push rod - so you can adjust the cup depth to include the preload distance. Then adjust the pushrod length to get the proper scrub pattern accross the valve stem. IMO, the most important thing is rocker to valve stem scrub pattern. Secondary is preload - as long as you are in the range of the lifters plunger travel.

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he's pretty limited on the scrub pattern with stock rockers, especially considering how they mount to the head.
i would include the preload in the overall measurement for piston to valve on that particular engine if it'll see higher than stock rpm.

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Why would you want to include preload - unless you are concerned about valve float? I assumed he went with valve springs that were applicable to the cam. It would be a safer way to go I suppose.

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To answer your question, no, you would not add the preload distance for piston to valve clearance. To do both proceedures properly, you really need an adjustable roller lifter to go along with your adjustable push rod - so you can adjust the cup depth to include the preload distance. Then adjust the pushrod length to get the proper scrub pattern accross the valve stem. IMO, the most important thing is rocker to valve stem scrub pattern. Secondary is preload - as long as you are in the range of the lifters plunger travel.

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he's pretty limited on the scrub pattern with stock rockers, especially considering how they mount to the head.
i would include the preload in the overall measurement for piston to valve on that particular engine if it'll see higher than stock rpm.

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Why would you want to include preload - unless you are concerned about valve float? I assumed he went with valve springs that were applicable to the cam. It would be a safer way to go I suppose.

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because factory lifters in that engine can pump up at high rpm.

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To answer your question, no, you would not add the preload distance for piston to valve clearance. To do both proceedures properly, you really need an adjustable roller lifter to go along with your adjustable push rod - so you can adjust the cup depth to include the preload distance. Then adjust the pushrod length to get the proper scrub pattern accross the valve stem. IMO, the most important thing is rocker to valve stem scrub pattern. Secondary is preload - as long as you are in the range of the lifters plunger travel.

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he's pretty limited on the scrub pattern with stock rockers, especially considering how they mount to the head.
i would include the preload in the overall measurement for piston to valve on that particular engine if it'll see higher than stock rpm.

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Why would you want to include preload - unless you are concerned about valve float? I assumed he went with valve springs that were applicable to the cam. It would be a safer way to go I suppose.

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because factory lifters in that engine can pump up at high rpm.

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and that is exactly why I asked this question, I assume you need to allow p-v clearance for a pumped up lifter

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I'm assuming that I need to allow the lifter preload in addition to the normal p-v clearance, or in this case the correct length pushrod (zero lash plus preload) against a fully pumped up lifter

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I'm assuming that I need to allow the lifter preload in addition to the normal p-v clearance, or in this case the correct length pushrod (zero lash plus preload) against a fully pumped up lifter

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I know little about the 5.7 ( although I own one in a Jeep ), but I run a large flat tappet Hyd cam ( over .6" lift ) in a SB. With my set up, I had to cut the existing notches in my pistons deeper to get adequate ( over what I previously mentioned ) pv clearance. Although I do have adjustable rockers,I still have to run some preload ( usually run +1/4 turn ). Just curious as to what preload is recommended in the 5.7 and what pv clearance you are shooting for? Also, did you make a cam change without any other valve train component changes - lifter, springs, etc.?

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