Can somebady give me some advise. Have just completed complete rebuild of 170. 250 head recoed and decked, 60 thou over, mild cam grind and olso decked, stock carby with over size jet. Was having trouble setting timing, managed to do that and then was running a little better. couple o days later it was surging a little on acceleration and the odd backfire and also exhaust manifold getting white hot, but not yet overheating. Spoke to early ford specialist and he said it was running to lean or jetted to small for engine upgrades. So I had bigger main jet installed and adjusted mixture, now it heats up straight away and over heats after small amount of driving and as it gets hotter it runs like a hairy goat. Mechanic suggested it could be timing related and be to retarded. I am not getting any effect when I remove vaccuum from dizzy whilst setting timing. If any body has any usefull information or suggestions it would be greatly apprieciated.

Sounds like timing fella. My xd had a huge cam in it and was a nightmare to set timing!

yes rejet it and reset the tappets and retime.it .also let it run a little rich for a while.set the timing at 6/than8/than 10 degreesit shoud run on about 8 degrees.are the advance springs in dizzy ok?.they can cause hassels if you dont have stronger ones in dizzy

if you're still having problems with the 170 I'd go to the earlyfalcons.com discussion forum and either do a search for previous overheating topics or post your original message - there are a few guys there who know everything about using the later 221/250 heads on the 170 and associated problems/fixes

here's their forum:
http://au.groups.yahoo.com/group/earlyfalcons/