queston about a 426 kit

[400exkid05]

hi. i have a 400ex and im about to rebuild it and put a 426 kit in should i run a 13:1 or should i do a 11:1.....and also if any 1 has a 426 in there ex..when then rebuilt it did u guys just bore and hone or did u resleeve and how thick was the sleeve after the bore and how does it run and does it over heat if u just bored it out.. let me know thanks

[underpowered]

On the compression, i would run 11:1 for two reasons. 1. you can still run pump fuel and 2 if you are still using a stock rod, 13:1 will likely overstress it.

I am running an 11:1 426 on just a bore and hone. the sleeve is pretty thin, but i have nt had any heat issues and it runs cooler than my most 440's i have seen.

[400exkid05]

y will it put stress on it????

[underpowered]

The extra compression force on it. I have seen them hold together, but i would not risk running a 13:1 on a stock rod.

[400exkid05]

they dont make a 12:1 for the 426 right

[400exrider707]

I would assume someone makes a piston between those two compressions in 426 bore. Also anything over 12:1 just opens up a whole other can of worms. The rod can be a factor, as well as the head studs, and blowing head gaskets, then race gas, and so on. If you want all out performance at any cost, then go for the higher compression, but if your a guy on a budget doing all of your own work, like most of us, then get the 11:1. JMO.