| Re: 289 heads--289 4V |  | ||
| Re: Re: 289 heads--289 4V -- Old Guy | Post Reply | Top of thread | Maverick Message Board |
|
Posted by: wm ® 2001/07/12, 16:22:21 Author Profile |
:::I found a set of 289 heads with the following cast into them
:::"289 4V". I assume these are the 289 hi-po heads. obviously the 4v means 4bl carb but are these heads really any better than other 289 or 302 heads. ::... ::The heads are listed for years 64-67. They have small chambers at 54.5 cc. The compression ratio they would give is dependant on the year 302 used on. Years 68-72 expect 10:1, 73-76 only 8.3 and 77, 9.3. Valve size 1.78/1.45. Opinion is except for a gain in compression they (may) provide, there's no gain in porting or valve size. As for worth it depends on who wants them. A Mustanger might kill for them to make his engine a (factory) HP ::spec for the way he wants his car equipped. Best heads from a breathing point of view would be 69-72 351 2v. They bolt on but attention must be paid to the head stud size holes. May need to use washers under the head bolts heads. Also not recommend 289 4v heads be used on a 351 for street use as the ratio would be over 11:1 with small valves ???!!!. ::I'm sure Old Guy can add some info and other recomendations on this subject. ::Ken I agree with you all the way, if memory serves me right, the 289HP heads had screw in rocker studs for adjustable rockers and a slightly different push rod hole to act as a guide plate. The flow test on the stock 289 head reveals that it flows a little worse than the stock 351w, however when ported and valves are back cut with some bowl work, they improve quite a bit. But the chart on the 351 with same Mod's, shows a lot more cfm's than the comparable 289. One must also take a look at the valve lift figures and see that the higher lifts (500 to 600) shows the best improvement in flow. Most stock cams are in the 400 to 450 range. All in all for stock improvement the 351's seem be the choice. I had a set of stock 302's converted to screw in studs, guide plates and 1.94-1.60 valves, I gasket matched them and ran them on my sons Mav drag car. They performed very well for the 900 or so dollars invested. Several years and a couple of valve jobs later, I invested 1100.00 in a set of Performer RPM aluminum heads. Out of the box with no mods at all, the Mav went from 10.50's to 9.50's with no other changes made. My point is factory heads are just that, good street performance and reliability, but for the money spent to use them for performance and HP gains, a few bucks more will solve a lot of breathing problems or lack of for that matter. I wouldn't have expected a full one second gain with the after market heads. Moving a full second from 17 to 16 is one thing but 10.50 to 9.50 is impressive. You got a lot of bang for the buck. THanks to all for their responses |
| Post Reply | Alert | Original message Top of thread Return to the MMB |