I have my 400ex in the shop getting a wiesco 440 kit installed.I am getting 12.5-1 piston,
hrc stage two Cam.Can i run pump gas or should I add octane booster?
My other mods are fmf hi flo header,fmf power core 4 muffler,k&n air filter,dyno jet kit .Also should I use synthetic oil? Any other suggestions welcome.
Thanks, ex kicks azz

 

your builder should know. i just finished a 426ex and it runs on race gas, it gets a little better throttle response

 

yup, u will need race gas, anything over about 11.1:1 in a 400ex will need pump gas i think

 

race fuel is reccomended and supposed to be run in anything over 11:1 compression. the above post was written backwords.

in the same idea, anything below 11:1 can be run on like 91 octane.

 

o ya sory about that, didnt catch it the first time

 

I've never had a problem with running pump gas (91 octane +) in my 440. It also has the stage 2 cam, edlbrock quicksilver carb, k&n filter and LRD exhaust. You could put a little pump gas in and see how it runs, if the power is there and you hear no pre-det your all good. If it runs bad add the good stuff.

 

you could mix half and half.