race gas in 440?

[veddersbetter]

I just bought a 2000 400EX with a White Bros 440 kit....no cam or anything....just 440. The salesman that sold it to me told me to only run race gas..100+octane. Ive dealt with high compression engines before and never had to use anything past 93. Is there anything I could be missing?

I personally like to run straight race gas in my 400 ex. I mix it with klotz 4 stroke upper cylinder lubricant. My 400 ex has a white brother e series and the timing advanced 6 degrees( if the offset woodruff key is accurate) This might be overkill and it costs quite a bit to do it but Ive got peace of mind that it wont detonate and I can tell better throttle response(sounds crispier) on race gas. Im probably gonna swap over to alcohol when I have time to put a dome piston in it. Again these are personal opinions and it might be a waste of your money.:) :D

[VegasEx'r]

Did the guy tell you what the compression ratio was? If you're under 11:1, you'll be okay w/ premium pump gas. I have a 416 w/ 10.8 CR & the advance key, and I noticed a slight ping at WOT, so I started using a 50/50 mix. Of course the ping went away, but I also noticed a huge difference in throttle response & temp. Play around w/ pump gas, race fuel & mixes of the 2 until you find the right combo that doesn't pre-detonate.

[rob-u/21]

I've got a Duncan 440 national kit and the people at Duncan told me I need to use race fuel. They recomend I use VP race fuels. C12 to be exact. I would also recomend for you to go and do the cam job to complet your 440 engine.