Its been afew years, (make that alot), since I've worked on one of these motors, so excuse my vague memory. Had a twin carb "s" when I was younger and did the headgasket in the driveway. They not to complicated.
Has he already bolted the head on? Did you unbolt the tensioner? I cant remember the exact system of chain tension on them..... getting to old (both me and the car
)
Find the timing mark on the crankshaft pulley and rotate it round to TDC. At the same time get the valves on No1 cylinder to both be closed, ie both inlet and exhaust lobes should be pointing away from the valves. You should see a mark on the cam sprocket that will line up with a mark on the head looking through the sprocket. Bolt everything up, getting the distributor to just beyond firing position for No1 cylinder, and you should be about right with afew adjustments of timing.
Unless of course my brain functions have deteriorated over the years to the point of dementia?