Classic/Antique Car Repair: Starting Problem, ford flat head, cam shaft

Question
I own a 1948 ford coupe with it's original flat head v8 engine (It was completely rebuilt many years ago).
Problem- When attempting to start the engine, I would get a grinding noise. I purchased a new solenoid and had the starter rebuilt. Problem still persistes. Removed sparkplugs
& turned cam shaft with long handled socket wrench to get some idea of the resistance. Very hard to turn. Ordered a maintanance manual online hoping it would give me torque figures. No such luck. I am getting very frustrated. Hopefully you can provide the assistance I need. Thanking you in advance, I am

Sincerely yours

Bob Sims  

Answer
The figures for maximum turning torque on an eight cylinder engine that I have always used is 40 foot pounds. And that is on a fresh rebuild. I use a beam type torque wrench for this job so that I can read the torque. If the engine has miles on it then the turning torque will be lower and I have pulled engines down that will turn at 5 foot pounds of torque. One question, did you replace the starter drive when the starter was overhauled? My 41 Ford flat head turned at 35 foot pounds when I installed it.