Posted by N8 on January 19, 1999 at 21:28:32:
In Reply to: Re: 289 heads posted by T.L. on January 19, 1999 at 19:30:55:
what are you refering to when you say "valve job"? a full seat/ valve grind or just keep the valves in order and relapp them upon assembly?
: The valves and ports are the SAME size and only the Hi-Po heads had adjustable rockers which doesn't matter anyway because you can use adjustable rockers & guide plates with a hydraulic cam. He would have to install hardened exhaust-valve seats anyway if he had a pre-1975 302, and a valve-job is necessary when rebuilding any set of cylinder heads. Competition Cams sells 1.84/1.54 valves for these heads as opposed to stock 1.78/1.45 and these new valves are actually better for the street than 1.94/1.60 valves that are in the aftermarket heads...
: : Yes, but why would you want to put them on. If I'm not mistaken the Hi-po 289 had mecanical lifters with ajustable rockers, which you'll need to change to the same as the ones that are on your 302 heads. Also the valves and ports are smaller on the 289 head which will restric air flow. The only benifit is the smaller combustion chabers, will raise compression, which intern needs high octane fuel. Also you'll need to have hardend valve seats installed to burn unleaded fuel, and if your going to do that you mine as well have the a 3 angle valve job done and have the ports opened up, which will cost you an arm and a leg. If your looking for better performance you'd be better off buying a set of after market heads that have all of this done and flow ten times better that any stock heads.
: : : Will '66 289 hi-po heads fit on a '73 302?