Ok, after about 5 posts regarding cams, heads, and my 289 in general, I think I've come to a good conclusion; Because of lack of $$$, I'm gonna have to stick with my stock heads, but I will have them ported/polished. The cam that I've found to be optimal (on desktop dyno) is Comp XE256H. According to desktop dyno, with this cam and worked heads, I can get 320 ft lbs @ 4000 and 280 hp @ 5500. Much of an improvement to my current setup which is calculated to have 301 ft lbs @ 2000 and 208 hp @ 4000. Furthermore, if I enlarge the valves to 1.88 and 1.6, thats 4 more ft lbs and 13 more hp. Does this sound right? Do you think I should just have the heads ported/polished with the current valves or do you think it would be worth the money to enlarge the valves? Thanks for your help, I can't wait to wake this motor up!
go to 1.94/1.6 valves (Ch*bby size) at the same time. Theres little point in a port/polish and NOT getting oversize valves. Dont forget to check piston-to-valve clearance w oversize valves and the bigger cam.
before you drop the money on the heads, find out the total price.. by the time you pay for new valves, guides, seals and the port work.. you may have spent almost as much as a set of aftermarket heads.. as for valve clearance... check it.. dont assume that it will clear..
Yeah, as stated above, I would find out what the port/polish/machine work will cost. I just looked over at the trader section under engine parts, and there are alot of options for $500 or less when searching for heads.
Well if I just waited and got better/real heads later, how well will the cam work with stock stuff? and do those "dyno" numbers sound right?
the additional shrouding resulting from the bigger chevy valves pretty much cancels out the added flow area. I'd go with 1.84/1.54 valves, like the early 351 heads, along with a good three angle valve job. Either way, both are better than stock..... Make sure whoever is porting the heads knows what they are doing. Some guys just polish the ports and say they're good for an addtn'l 100 hp. Make a visit to their shop, see if they have a flow bench, etc.
for the moey your'e going to spend on a good vlave job, bigger valves and a port n polish, you'd be able tobuy the windsor jr's i recomended. if you're set on stock heads check out www.powerheads.com guaranteed to flow better than just about hand ported and polished job and will probably be about the same bucks
