High rpms on a Mopar not a problem in my option. The main reason I run them is when I was young dad had a 66 Chrysler 361 cid, most driving at 100 mph plus, rpms at 3500 plus. We put 660,000 miles on this car over 20 years like this, oil and filter changers every 2,000, the only work on it the was a couple of timing chain and gear sets, and at 380,000 miles new rod bearings rings and oil pump, no re-bore or other parts, oil would be down 1/2 quart at oil change when car was parked, pulled engine and put in my 70 Coronet for another 35,000 miles still ran good when I parked that.
74 - 318 truck drove the same for 230.000 miles no problems there either till the timing chain chain broke and bent valves( at the track with engine near red line ready to shift from 2ed to drive ), could have fixer easy most likely but gave a good reason to install a 440 in the truck.