Personally, unless you need numbers matching componets or are doing a pure restoration I wouldn't put time or money in a set of 289 heads, even if they were free. The the runners and chambers are horrible. Modern heads (iron GT40, GT40P, etc.) are so much better to start with and cheap nowadays.
Very true but aftermarket heads are not in my budget right now and I'm not a racer (although racing is way cool). Theese heads I got were free, and one of the sets has already been rebuilt, along with Comp Cams roller-tip rockers. They belonged to my friend's dad who passed away in '99. He gave them to me along with 2 engines. They have the same size valves and ports as my current 302 heads, but a slightly smaller combustion chamber. I just haven't pulled them off the engine yet so that I can "CC" them. My book says they are 52-55cc and that 302 heads are about 57-60cc. What I didn't know was how much of a compression gain it would yield (probably only 4ccs difference), which is why I posted the question here. I certainly won't be spending a bunch of money on these heads trying to trick them out. Aftermarket heads are the only way to go when it comes to that, but I just may bolt these on as-is and use them for awhile...
Well duh. I think I might use free, rebuilt, small chamber heads too. lol. That small chamber is worth something. I'd self port them though. I'll be hanging on to my 66 heads also. My boys may get them after they are sllloooowwwwllly reworked and they grow up enough not to kill themselves with them.
I have heard on Ford small blocks the 5cc = 1 point compression, and 1 point in compression = 4% increase in power. I have seen dyno tests on various engines that would agree with that. Let's say you will gain 1 point in compression. If you have a 150hp engine, that would be 6 extra horsepower. I would suggest selling the heads on ebay and getting a K&N air filter!
When people say "one point" in compression, does that mean like from 8:1 to 9:1? Or does it mean like 8.5:1 to 8.6:1?...
played around My CR calculator says .65 increase in CR going from 60 cc to 54.5 cc. .04 gasket, 4.03 bore, 5cc dish(valve reliefs only), .010 deck. .64 if std. bore. If your chambers are 59 cc now, .56.
I just found one of the most complete web sights for information on castings, displacements, valve size, factory specs in general. Just look up the make and year in question and don't forget to scroll down as there is more then 1 page for each year. I found it while trying to reseach the heads I'm working on right now. This is one that has to be book marked by everyone that works on engines. http://www.nhra.com/tech_specs/engine/index.html Enjoy Eric J
That is cool. Bookmarked. Although I have to admit it just made me more unsure of 66 289 chamber sizes. Shows two cc numbers, but the same casting for both, flat and dished pistons. So my first interpretation is that they are including pistons in the cc numbers. But then neither of the cc numbers are what I've seen listed for those heads, and even the dished are smaller than 54.5. Now I want to measure them even though it will be years before I use them! I was looking at affects of higher cr and found this article, very good. Lots of tips for running higher cr. http://www.popularhotrodding.com/enginemasters/articles/hardcore/0311em_power_squeeze/ The hp/cr increase table is weird though, everything else I saw showed percentage gains decreasing as cr went higher. (maybe they are showing direct hp gains and I just misinterpreted it) Happy with what I'm doing, should get about 3% more hp, better torque across the rev range, especially down low, and better gas mileage. Upping cr is definitely going to make that bigger cam behave nicer off idle.
