briggs flathead info.

[jimh]

I was wondering how much I could safely shave a 5hp briggs head,and still have plenty of valve clearance. I dressed up the ports a little and have a carb that flows about 8% more air and fuel. Plan to run a header. Don't want an all out race motor, just want to make the best of what's already there.

 

[philip metzner]

jimh, some folks will not agree, but i wouldnt do it, unless just a little clean up to get it flat. flat head engines are prone to detonation problems, and that can knock the rod out of a engine quick. its better to work on air flow.-phil

 

[Backyard Builder]

Shaving the head will only kill the already not-so-good airflow. Forget about compression when working on a briggs flathead, think flow. Remove the eyebrow and port match the carb to the block. An aftermarket cam is also a good upgrade.

 

[GTO]

Any pics on plucking an eyebrow? :wink:

 

[minidragbike]

Milling the head works, and taking that bump out of the head works too. But the problem is that it's not allowed in some kart classes. To get the most compression you can from a flathead you will want to cut the complete deck shorter.

Not a lot only around .020". It may not sound like much but it makes a big difference in air flow and compression. Cutting the eyebrows also work, but make sure you don't cut to much. Porting and seal is the best thing to do with a flathead.