Rockers and leaking down lifter

Hi all,
1975 Fury 318 LA. around 50T on rebuild, Daily driver... I've been having an occasional lifter tick... Now that work is over for a couple of months I've decided to move on the project.. I pulled the valve cover on that side.. at first nothing seam out of order .. nothing way lose. looking at the rockers all were marked 59 L on the left side of the cylinders and 59R on the right side of the cylinders.. I noticed that on cylinder #8 the rocker on the left was just marked with an L no number is that OK??
Started the motor and it took awhile for the oil to get up to the shaft? NO real splashing just running down the springs. just an idiot light no gauge for oil pressure, going to get one.. Light usually goes out almost right away.. While it was running I took a screw driver and pushed on the push rod side of the rockers all made no sound except the intake of #6 and it made a very nasty knocking sound not a ticking sound.. so I'm assuming that is the bad lifter, does that sound right??
So my plan is to install a new can/lifter kit with timing chain/gears

COMP Cams K20-222-3 - COMP Cams Xtreme Energy Cam and Lifter Kits​

and have the heads done, I just lapped the valves when I did the rebuild, cam kit comes with springs and such so I figured it would be best to have the heads done. Just under 100T miles on car.

does that sound like the right way to go with this adventure??

Whatever happened to this adventure? Curious to see how you made out.

Personally, I don't like renewing the top without doing at least the rings and cyl walls. Your rocker arm is fine. Is your cam bad? Bad lifter? It's hard to say if you have a problem without being there.

UPDATE..
So I've pulled it apart.. Tho I haven't pulled the cam or lifters yet I'm waiting on the heads to be done .. and now that is a waiting game.. they sent the wrong valve spring locks in the cam kit.. I needed 2 and 4 groove locks and they only sent a full set of 4 groove.. GGGEEZZZEEE. So they are sending me an 8 set of 2 groove at 1/2 price Still it should have been the right set to began with..it cost me more $23.oo more.. Should get them on the 10th so I can get them to my machinist to finish the valve and new springs job.. When I get the heads I'll install them and pull the cam and lifters and look them over.. as well and a new chain and gears set.

I'll up date with what I find on that lifter #6 intake that was making the noise..

Bird 426 said:

Personally, I don't like renewing the top without doing at least the rings and cyl walls. Your rocker arm is fine. Is your cam bad? Bad lifter? It's hard to say if you have a problem without being there.

Click to expand...

HI,
Yes the bottom I rebuilt just a few years ago and only has like 30 to 35 thousand miles on it..

Up Date
HI,
Here's some pictures of the lifter that was making the noise and the cam lobe. All looked good, the lifter has no marks and is still has its belly, I didnt take it apart yet but it has to be in the plunger or plunger spring.. the cam lobe look great no marks or uneven ware.. it has like 30,000 miles on it..