I've been running the 305 in my '59 Ford truck for the last 6 years as everyday driving as a salesman. It's been a great engine with over a 100,000 miles. All this using the wrong heads and that's my problem I now have. I can't find the right heads. If I use the stock head with 1.84 valve, I'm told the "light casting" heads will crack. Let me know if you decide on using the 305 and what heads you plan to use