So This is my take away from asking if 20W is to heavy for my 340.
1. The question is application specific.
2. It depends upon the bearing clearances which is a function of engine set up and wear (mileage).
3. Depends upon ambient and operating temperatures.
4. Depends to a small degree on how you drive and what your looking for.
5. Depends upon what your oil pressure is and what you’re currently using (oil weight).
If I left anything major out above feel free to add it.
BUT in general 20W-50 is commonly being used in the 70’s small block Mopars and I am sure in 327’s and many other engines across the board.
In my case it’s probably what I used to run and what I had in the shop. I have it now in my car and when I am up to the task in getting it running will assess the oil pressure and go from there.
Thanks for all your comments and suggestions guys!
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