Based on experience, what brands of engine oil are other members using on their daily driven flat tappet engines. I just read about oils with API service rating of SM are not sutable on older engines with high lift cams and heavy spring rates. Any suggestions are greatly appreciated.

once the engine is broken in newer oils will have enoufgh anti wear protection for stock to mild flat tappet cams. ive run 10w30 valvoline in my 440 for 60,000 miles and havent had any oil related issues (knock on wood). my dads run 10 40 castrol in his 383 for 15 years with no issues. however the 383 is bone stock and 440 mild. 4.0 jeeps have flat tappet cams and i havent ever seen one get wiped out and nobody puts any SPECIAL oil in those. i talked to the valvoline rep and he said" we are confident you will not have any issues running our regular motor oil once broken in, however during break in you need high zink levels." if your worried gust run a high zink oil like valvoline racing oil.


as far as oil weight goes that will depend on what kind of temps you drive in and your oil pressure you desier. i like 10w30 under 55 degrees and 10w40 above 60 degrees.

Here's a link to another Mopar Forum that I started on Engine Oils,,,Some good information as well.
MoparStyle Thread on Engine Oil

I did the cam break-in with Castrol 10w30 and a bottle of GM's EOS. Once the engine is up and running in the car I'd use Shell Rotella T 10w30 and one litre of Royal Purples new engine break in oil for about 500-700 miles. But I'm wondering about the ratio, I have an 8 quart pan, any thoughts...

I run Rotella T diesel engine oil. Available in 10W30 and 15W40. It has about twice the zinc car oil has. I also add STP for a little insurance.

I wonder how Lucas additives would stack up. I've used it in my newer vehicles and it helped rid the clattering valves in my 03 van. They also carry an Octane booster,,,and I guess fuel and fuel additives is another topic for discussion.

lucas octane booster doesnt work.

I've run Royal Purple for years. I ran it in my 73 Dart with a flat tappet motor, hyd first and then to a solid. I run it in my Powerstroke truck, my hyd roller motor now, my golfcart, my kids 4 wheeler, my generator, my lawnmower etc. I even used to run it in my Harleys. It really kept the harley engines cooler when we were riding in parades (Shriner). I even had it in my 65 VW Manix street dune buggy. I have never had an oil related failure. I lost a solid flat tappet a long time ago with an oil failure with Castrol. That caused the switch and I've been happy since.