Purple Shaft 280/280 cam

There is somthing on your freinds motor that has been changed from stock.
Thats not to big for any stock motor.
The only thing you need to watch out for is the rocker arm hitting the valve guide boss(top of valve guides)
what are you trying to do \\
Build it the same as a stock motor.
The only thing that it has, thats differant, will be the cam
Use a small hyd. cam with the right valve spring and your done.