i was wondering what should i bore my 400ex out to to get the most power out of it? iv heard people say that they get the most power out of 426's, it this true?

 

A well built 426 with head work and a cam will out do all but the race only 440's. If built right and taken care of will last longer and run cooler.

 

iv heard that if i go to a 440 then i will be changing gaskets like no other if you dont go with the oversized head studs. do you have to get the oversized studs with the 426 or will the stock be ok?

 

You can use the factory studs, but since it's apart I would just go ahead and put in the heavy duty studs and avoid any issues all together. The main failure of the head studs is high compression. A well built engine will stay together. A dyno tune will go a very long way when you build an engine to get the most out of it and to make sure the A/F ratio is correct. A good tune will prevent any detonation and blowing of head gaskets or pulling studs.

 

sounds good i think im goin with a 426 kit now...

 

That's what i'm doing with my '08 400ex. If you have the funds, send your head out to Trinity Racing for a stage IV port.polish, good cam matched for your combo, and a 450r carb. You'll kill the 450's out there.

 

yeah i raced a 450r today and he beat me by about 1-2 quad links...think it would be nice to have a re-run to see the difference after the bore...

 

After you get the engine done, go ahead and spend the money and get it dyno tuned. You want the most out of it and make sure everything is good.

 

After you get the engine done, go ahead and spend the money and get it dyno tuned. You want the most out of it and make sure everything is good.

 

do you know a rough figure $$ on gettin it dyno tuned..and were would i get that done at?