I've recently installed an IMS 440 big bore kit (11:1), WB Track Cam, FCR 41mm carb, and Big Gun complete race exhaust system in my 400ex. Does anyone know what kind of horsepower and speed gain I will get? I've tried to find horsepower curves for power upgrade kits on the net but with no success. Anyone help?

 

my guess is somewere around 37 - 40 hp

 

Id say between 35-37

 

GT Thunder's website http://www.geocities.com/gtthunder.geo/gt1.html has a slew of dyno tests. Spend some time browsing; your WB track cam should perform similar to their cam. The lift/duration specs are the same, although the lobe centers and ramp angles may or may not be.

On the other hand, you might not like the results they had on a fully built motor using the Big Gun exhaust. I don't remember if it was a BG race exhaust though...

 

Without porting I would say real close to 38. It will be a very notciable difference over stock.

 

Do a port job on it and you will get great increases. you can be up towards 43 or so then. it is worht the money..