if you have 10.4:1 compression is it absolutely nessasary to run 91 octane even if your not pushing the engine? thanks
If you've got an honest 10.4:1, more than 91 would be better. Of course, if that's the factory compression rating, it's probably in reality lower than that. There were an awful lot of 327s that were "factory rated" at 10.5:1 that really worked out to 9.7:1.
The Jalopy Journal
