I keep hearing that if you go with anything higher then a 12:1 then you should replace the stock rod. That's fine, but will you be able to tell a diff in power from a 11:1 to a 12:1?

 

Also, what's the deal with the gaskets? I have read that some people go with no base gasket, just some rvt or somrthing like that, and go with an XR head gasket. Exactly what does this do, and is it okay to not run a base gasket? Thanks.

 

i can't tell you the differnce in power between 11 and 12:1. i have been told it isn't great. the ex is supposed to respond good up to around 11:1 and there isn't a large difference after that, but i am sure it would help with low end power.


i currently run a thin head gasket and no base gasket. this is because you will raise the compression a bit this way and you get a better flame travel accross the top of the piston. the xr head gaskets are fine. i used the cosmetic flex steel ones. i think the cosmetic ones are a tad thinner from what i have read, but i can't promise you that. on the base, i wouldn't recommend RTV. the hondabond won't break down in oil and is supposed to be a bit stronger holding. i have had good luck with it.

 

Cal, thanks for all your input, its really been helpfull. So with your setup are you using the cosmetic XR head gasket, or the one for the 400ex.

 

i run the Cosmetic flexsteel thin head gasket. i believe this is different from the xr. the xr is made for a stock bore or a 406. after that, they make one for the bore you have. they do this because as you go larger on the bore, the gasket should be bigger. well, you don't have too in a larger bore but i do since they are made. the thin cosmetic or the xr gasket should do fine for you in you run a stock bore or 406 though. mine is made for a 426, because i run a 426. by the way, the 400ex and the xr gasket is the same thing besides the xr is thinner. the deck height on 400ex's is off a bit so going with the thinner gaskets will not only raise the compression a bit, but it will also provide a better quench area and flame travel across the top of the piston.