Your existing carb jetting 98 primary jet .070x .037 pri rod 95sec jets.
to lean down the primary crusie swap the primary and secondary jets around
ya you read that right.
New jetting 95 primary jet .070x.037 rod 4" power spring 98 sec jets.
try that.... reset the idle... how is the throttle responce from idle ,, from low cruise,, from hiway cruise.
Do not expect much from this big cam at 3000 or less rpm It wants to rev.
Keep the rpms up when it is cold .. Do not idle slow when cold. warm it up with plently of rpm.
Is the distributor advance locked out? 36deg BTDC full time.?
fix the exhaust leak ( header gasket??) Get a vacuum gauge so you can watch the manifold vacuum while driving it.
re: cruising in over drive.. try not to cruise at less than 3000 rpm... The motor with this cam likes to run.
Keep it where it is happy. The lowest rpm is not the best rpm..
Tell me how that works.