Does Onpol bore out the runners on the IM? If so, to what size? And last, would it be worth the 3/4 hours to port match the engine block to the runners on the BIM? I have the time and the tools, Im just wondering what type of gain I would get, if any. Any help would be appreciated, thanks!

 

The engine Intake ports are larger than the IM ports.

Onpol ports out the IM openings to match the gasket between the two.

If you try it yourself, be damn careful, the injector seat is right at that opening and if you screw that up, your injectors won't seat/seal right

 

I'm actually having someone else to it, but will there be any gain?

 

Yes. If its done right.