Back early racing i seen a L bracket used on the right side to relocate the rocker shafts could have been 3 /16 steel / stainless - and they shimmed the rest for end play - cant remember but they might have raised the rocker shaft to get a bigger cam longer valve stems - not to take away from the porting of the heads - the ratio is 1 to 1 so i also seen some had re made the rockers and splined the two haves so the ratio could be changed for faster valve action

not much the racing bunch did not try to get an advantage over the others

i dont know if he is still alive but Pete hill was the knuckle guy top fuel back in the day his shop was in Virginia - i am sure u tube has films

that was with out any doubt the loudest fueler i have ever heard and his wife would push the bike back after a burnout to the line - had the pleasure of pitting next to him a few times - great guy fast bike

 

I dont know the EVO rocker ratio but I saw S&S offers roller tip rockers that are much shorter and could be a good fit. I do like the bolt on end plate look.

I looked up Pete Hill, I read he was a teen in 1948 so if he's still alive he's no spring chicken. I see his son posts on facebook but no mention of his dad.

 

I am pretty sure Pete Hill is still alive, a picture of him in Easyriders last month with Bill Page.

 

This bike was at TROG in Pismo in 2016:

https://www.sideburnmagazine.com/pos...koslow-super-x

Took three guys and a starter wheel to get her going. Sounded nasty, in a good way, do not recall if it was fast.

 

Picked up these two heads, both had the diving boards broken and poorly welded back on. Perfect because the diving boards need to be cut off for this application anyway.