for those running guidep lates on Lt1's/
for those running guidep lates on Lt1's/ I'm asking those who have switched out to non self aligning rockers on Lt1's and are now running guide plates. I'm going to be running the 503 and I'm running the comp high energy 1.6rrs. I'm using comp guide plates and 7/16 studs. Did the addition of the guide plates thickness make a big enough difference that you needed to change away from the stock 7.2" pushrods? I Can't imagine it would really change much if it did maybe 7.205 or something like that.
The cam change alone may change the pushrod length. Then add in the guide plates and different lifters, you need to measure. Motors can get wrecked pretty easily if the pushrods are the wrong length.
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IMO, the plate should not be a factor. The rocker is going to sit at the same relative position to the PR and valve stem when you adjust it. It'll just be sitting at a different thread height on the stud.
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use the RR studs, ARP, for guide plates...they have a recessed shoulder to compensate for the guide plate thickness
Regarding guide plates, use the ISKY adjustable if you want the RR to line up EXACTLY as they should vs using one piece guide plates on Gen 2 LT1 heads
Always check PR length. For a non decked block and heads (read using stock untouched heads & block) you should not need a different length but it is always advised you check. Use a Sharpie on the valve tip, lash the RR and rotate the engine 2 turns by hand, remove RR and look at witness mark. You want a narrow, centered, mark. One closer to the exhaust side of motor needs a shorter PR. Mark closer to intake needs a longer PR
Regarding guide plates, use the ISKY adjustable if you want the RR to line up EXACTLY as they should vs using one piece guide plates on Gen 2 LT1 heads
Always check PR length. For a non decked block and heads (read using stock untouched heads & block) you should not need a different length but it is always advised you check. Use a Sharpie on the valve tip, lash the RR and rotate the engine 2 turns by hand, remove RR and look at witness mark. You want a narrow, centered, mark. One closer to the exhaust side of motor needs a shorter PR. Mark closer to intake needs a longer PR
My last setup I put .060 lash caps on my valve tips, checked the sweep and it was still acceptable. Always check your sweep whenever you change anything in the valvetrain or cam.
ShoeBox is correct, and at least from my personal experience. The guide plates should not change pushrod length. These are not pedestal mount rockers. They 'float' on the rocker stud threads until you get the lifter preload set, then lock into position when you tighten the set screw on the polylocks. As far as guide plates, IMO adjustable are the best way to go (I personally run the Isky's as mentioned above). Be sure to check the part number on the Comp guide plates you mentioned in the original post and make sure they are NOT for Gen 1 old school small block chevy heads. Those are close, but the slots are not the exact same center to center distance between the pushrods as the Gen 2 Lt1 so they will not quite fit right. I made that mistake years ago. Either way checking the pushrod length is the only for sure way to know what your motor needs.
