I'm trying to help out a friend order some engine parts for his '66 289 out of a mustang. The machine shop that did his heads said to make sure he orders the right timing chain/gear set for that year block because there is a difference in which using the wrong set will cause the gear to rub against the block. I looked in my PAW catalog and only found that the difference would be a one pc. fuel pump eccentric or a 2 pc. eccentric. What are they talking about?
Thanks in advance.

Mike

 

He's talking about the width of the timing chain and gears. Early engines used a wider set, which measures 1/2" wide at the chain, In '65 they changed to a narrower 13/32 chain. So, if you put the thick chain in a late block, you'll have an interference problem.

The early, wide chain used a cast-iron cam sprocket, and the later, narrow chain used a sprocket with nylon teeth, except for the 289 HiPo. The HiPo also used a thicker thrust plate. Other 289 engines, both early and late used thrust plate that measured between .22 and .25 thick, the Hipo used a thrust plate that was .375 thick.

Is your friend planning to use a stock timing set, or is he upgrading to a roller set?

With an aftermarket set, you shouldn't have a problem. Summit has quite a few to choose from. a couple even come with a matched thrust plate.