351 heads on 289
 

Is it a good idea to put 351 heads on a 289?
What kinda of horse power gain can I expect?
And would you just port and pollish the 289 heads?

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JASON HIBERD

Only use the 351W heads if you can find a good set of 69 or 70 model heads. All the others used the same ports and valves as a 302, or had larger chambers--so you lose compression. These heads work good on a 289--about 25 horse or so more than the 289/302 heads. Check the post by IIBAD4U. I wouldn't bother porting and polishing the smaller heads, by the time your done, you could have just bought the 351W heads, or an after-market head.

I have read in a "MUSTANG & FORDS MAGAZINE" article that 1969 thru early 1974 351W heads had larger valves than 289/302 versions. All heads produced after 1974 have the small valves.

True about the valves, but after 70, the combustion chambers were enlarged to 64 cc. Too big, in my opinion, for a 289. Hence the only really good 351 heads for this swap are still the 69 and 70 models. http://www.mustangworks.com/msgboard/smile.gif

Actually, all 351W heads from '69-'77 had 1.84/1.54 valves and 60.4cc chambers. The '69-'70 heads had larger intake ports and flowed a little better. I have a set set of '75 351W heads that are nearly identical to my '70 heads except for the above mentioned difference.
Jon

Hey don't you have to change the intake manifold with a 351W head swap? Old gray brain matter straining again.

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Dave Folk, '87GN, '84GT, '79 T/A 6.6 convertable

No, you use the standard 5.0/302 intake manifolds. Now 351 Windsors do of course use different intake manifolds than 302/5.0s.
Jon

I stand corrected on the details, but still stand behind the basic idea that the 69 and 70 model heads are the only ones worth considering on a 289. In my honest opinion, for the $$$ invested, I'd rather own some after-market heads anyway. Iron GT40's would flow about the same and the price is hard to beat. I run Iron Windsor Jr.'s. I pocket ported them myself, and can't even compare the power to the stock heads. No dyno #'s, but it feels like 50 hp. Not bad for $700 (used w/ roller rockers) http://www.mustangworks.com/msgboard/smile.gif http://www.mustangworks.com/msgboard/smile.gif http://www.mustangworks.com/msgboard/smile.gif BTW--I have better low end torque than before too.

If you use a 351W head on anything other than a 351, you'll need to use 351 intake gaskets, unless the heads are later than 77. The shape of the water ports is totally different than the 289/302 port. The front and rear intake gaskets should be tossed and silicone used, but the side intake gaskets for a 351W must be used in this application. The other thing is that the 351W uses 1/2" bolts, so you'll need to use a special shouldered washer to be able to bolt them up to a 289/302 since these motors use 7/16" bolts. Edelbrock makes the special washer, it is part # 9680

Are you sure that valve size between 69-77 are the same for 351W. Mustang and Fords mag also says after 74 they used the smaller valves.