I am building a 440 with a sumit cam and lifters. The pushrod length is stock 9.31 inch and the rockers are summit aftermarket. I am concerned that there is a great difference in off lobe lifter lash(colapse). This off-lobe commpression of the lifter varies from .045 to .120. What would be considered the max lifter compression off-lob? I'm use to chevys where we would expect .030 but I have been told that some older mopars used much more. Does it matter that I have this varience? please help Mike

i think you know the lifter fills with oil.

I understand that the lifter fills with oil so are you saying that the lash does not matter as long as the lifter does not bottom out like a solid lifter would? Is all the varience caused by rocker arms being different? Maybe this is just common mopar valvetrain and I'm used to much closer tollerance with other motors I have built.

You'll be fine at .045"-.120". I've seen lots of rebuilt heads from varying shops that had stem heights all over the place. When doing the many head gaskets on the 305, 350 and 4.3 V-6 chevs, especially 1989 and 1990, we would adjust the rockers back down to 3/4 turn past zero lash, on all lobes at base circle, then just turn the rest of them down to same thread count as the first ones and they always ran great. We did not take the time to adjust per shop man, as warranty time was putting the squeeze on us.

Yea, I've done many small block chevys and always gave the lifters 3/4 turn past zero lash, but this only gives .030 lash consistant on all lifters. That is why I'm concerned by the .120 lash on the mopar. Unless I here different I'll go with the varying lashes but it sure seems like alot as the lifter is half way compressed at off-lobe.

so.. whats your point?

I'm confused..are you using stock style shafts and rocker arms? did you pre-soak your lifters in oil? If you are using stock style shafts and rockers you don't need to set the lash just crank them down to 35lbs and check to make sure you have some play. Are you running a set of rollers? If so I's call the tech line to find out. FWIW that is a good cam in a mild 440.

Sorry, I should have said the rockers are stock style summit on factory shafts. I think my problem could be inconsistant rocker stampings as I am noticing a pre load varience from .045 to .120. I'm going to swap the lifters around tonight to see if the pre-load changes. Will the motor run o.k. with the .120 pre-load as long as the lifter is not bottomed out? I have posted this on other chats, and some say my issue is normal and some say it's not. I'm really not trying to make any point, just trying to understand what I'm dealing with before I destroy a good motor.

Is this a new cam lifter set? How do you know the lifters are "pumped up" If you ordered a set of lifters, cam, rockers, and push rods for a 440 you should be able to bolt it all up and go. I've never heard of anybody trying to set the lash on a hydro cam w/ stock rockers. Are you trying to use some 66/67 push rods? DO NOT OVER TORQUE the rocker shaft bolts and make sure the oil holes in the shafts are facing down.

Yes this is a new cam and lifters as well as the aftermarkert, stock style rockers, and factory pushrods from a 68 or later. As far a pumping up the lifter, this motor has never been started and the spring in the lifter is suffiecent to hold the rocker up (I have tried pulling up on the pushrod and the rocker does not move so I'm not sure what oil in the lifter would change as it would not hold pressure when the engine is off). I'm checking the lash with the motor not running. At this point I'm wondering if this motor may have had the heads or deck milled poorly at on time throwing the whole thing off. I'll look in this tonight. My question is still not answered as far as will this motor run correctlly with the .120 lash?

no idea I've never checked the lash on a hydro cammed BB mopar using stock valve train. They should move a smidge and that's it. You might want to prime the engine using a drill and priming tool the check them again. If the heads were cut you'd have issues with them hanging open. More likely the vavle job was not done to well and the seats are cut wrong or something.

Mystery solved thanks to thunderdart! I took off the rocker shaft and layed a straight edge across the top of the valves to find a very very botched valve job. The tops were all over the place! Just takes someone thats been there. I knew it wasn't right but my inexperience with mopars wouldn't lead me there. This valve job might work ok with adjustable lifters but it is no place on a stock mopar. You all might check your lifter hight after a valve job with a straight edge as a quick check on all non-adjustable lifters. Apparantly this happens alot. Thanks to all---Mike