360 build.

you asked about 340 cam wear
check the lifters
first keep track of their order!
you can butt two together and they should rock
if they are concave they are junk
you can place the bottom of one against something flat and it should rock and you should not see any light under the center


someone mentioned the 268 comp cam- a fine chevy design by UD Harold
and the 262 lunati voodoo
which has about the same lift with 6 degrees shorter duration
Like advancing the comp intake close point by 3 degrees to build cylinder pressure -(which is not a good Idea as it throws of the other 3 events)
It's a kludge for a to much duration cam
there is no place the voodoo would not outperform the comp especially on a lower compression motor
did OP post up his compression?
The problem with the old 340 cam design is the really long ramps and even with the long duration - not much lift
340 closes the intake late lowering dynamic compression
340 closes the exhaust late leading to intake dilution - which is why it is a smog cam in a late engine- like extra EGR
It opens the intake early allowing blow back , it opens the exhaust early which drains the power stroke- especially a big loss in a low compression motor
the 340 spreads out the overlap (makes it less) to 114 to compensate for these longer ramps which makes the opening and closing points even worse
now when I say early or late I mean compared to a faster acting cam- like the voodoo
did you see the head porting article in HotRod posted recently where they use a custom MM series solid profiles
same basic comparison here