I still try to use the recommendations of the '68 Owner's Manual


Note that the underlining was done by a Pontiac Service Manager in 1969-70. I had taken my 400HO into the dealer because the lifters sounded noisy. The service manager, knowing that my 400 was a 400HO, asked what grade oil I had used and I said 10W30 like the manual shows. He said I missed the small print that says the HO requires 30W. The lifters have been quiet for the next 39 years.

The oil change I did a couple days ago was conventional Pennzoil (what it's used most of it's life) SL code , 3/4 bottle of ZDDPlus, and an AC PF24.

As always, the longbranch manifold with the TH400 provided it's normal messy puzzle getting the filter off.