49 flathead rebuild. Fuel?
 

When I get my Flathead back from the rebuilder what fuel do you all use after.is there a lead additive? Do they install hardened valve seats? Thanks

Re: 49 flathead rebuild. Fuel?
 

A 49 should have hardened seats, but I would check with the builder. The fuel octane is going to depend on what you have done to the engine. Most flatheads are very low compress unless something has been done to increase it and even than low by todays standards. It should run on about any octane you can get at the pump. I am not a fan of ethanol, so I use non-ethanol fuel, which can be easy or hard to find depending on where you live.

Re: 49 flathead rebuild. Fuel?
 

There was no lead in gasoline in the early flathead era!

Re: 49 flathead rebuild. Fuel?
 

I have a freshly rebuilt 239 V8 59ab stock style setup and am running regular unleaded - same as my original everything I6 226 in the '49. The lead substitute products contain mostly clever marketing.

Re: 49 flathead rebuild. Fuel?
 

Thanks all of you for the reply. Thats an easy solution