When I was in the process of building my 302 HO, I ran across a lot of threads here that discussed the differences in the standard 302 and the 302 HO firing order. So, I did a search and found some good graphics at the boxwrench web site and then made a little one page reference sheet for both engine types. This is plain and very simple, but sometimes it's handy to see it graphically instead of just the string of numbers....
The Jalopy Journal
