Fuel Requirements '72 & Newer For the record, the 1972 Buick Skylark Owner's manual (page 51) reads: General Motors recommends the use of of a "good quality" unleaded or low lead gasoline with an octane number of 91 or higher. Should I use a "leaded additive" anyway to keep the "beast" healthy...or get more HP? stock engine (350-2) with 142,666 miles.
Again, I will ask. What RPM is aviation fuel designed to run at? Is it designed to run at 5500 RPM like our cars run at? What is the density of aviation fuel? Oh never mind. Just go ahead and use it. I give up.
That rating is "91 Research Octane". Currently, the rating you see on the pump is R+M/2 -- The average value of the Research and Motor Octane numbers. The typical Research octane value of today's 87 R+M/2 gasoline is 91, the motor octane typically 83-84. All 71+ motors are designed to run on today's 87 unleaded octane pump gas. I also use unleaded premium in my '65 electra, the 401 nailhead loves that stuff. I've put nearly 10,000 miles and 100's of 1/4 mile passes on that motor in the 2 years I've owned it, with no ill effects. It runs the same 1/4 times now as before. The total engine milage is 73,000. Of course, with the pre'71 stuff, this is just my experience, as they say, your milage may vary!!
So would it be wise to use 71 or newer heads when rebuilding my 70 455? Are all years of 455 heads interchangeable? Are some years of heads better for performance? Do the seats actually look different in the 71 and up heads?
I've got 67 GS 400 and I run 93 octane along with about $30.00 of Cam 2 every second half fill up. Runs perfectly!
#1. Redline lead substitute #2. The secret history of leaded gas #3. Marvel mystery oil for old buicks?
Joel, If my car wasn't outside right now I'd say you stole it! What color is your interior? And yeah, I use the lead substitute every fill-up. Like they say, it's cheap insurance.
I never waste time with any additives in any of my 455's. I don't use any as my daily driver anymore but the one I did drive everyday had well over 150,000 miles on it and I ran 87 octane crap gas (because I'm a tight waud) and it's still running. That motor has been in 5 different vehicles now but I have never had to put a dime in it. I only use race fuel at the track, otherwise, I save my money for gum.
