[downsideup09]

pros and cons? is it ever done?

[The Greek]

The 289 cylinder heads have a smaller combustion chamber and no provisions for the thermactor plumbing to hook up at the rear of the heads. Some heads have taller valve stems for use of the rail style rocker arms and pressed in rocker studs. You have a different design rocker arm set up than the later pedistal design. Some early heads I believe also had smaller valves and head casting does not allow for removal of taller roller lifters without head removal, uses the larger 18mm spark plugs. These are some differences that come to mind there may be more. The rare and expensive HIPO 289 cyl. heads had screw in rocker studs and were designed to be used with adjustable rockers and solid lifters. All the best,---Chuck