Flat tappet cam on roller rockers

Hello everyone!!

I wonder why there is so little information about roller rocker setup for pinto engines...

I am planning to use flat tappet cam and american 2.3 roller rocker setup for my Ford Sierra 2.0 drift car...
the engine will be turbo charged and in the range of 250-300hp(H-rods,cosworth pistons etc.)
The cam pillars will be welded and converted to needle cam bearings...

Here are some pictures of the modifications: