351 heads on 289

sweet65stang · 05-23-1999, 09:42 PM

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?

------------------
JASON HIBERD

66fastback · 05-24-1999, 01:46 AM

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.

MUSTANGROB · 05-24-1999, 02:55 PM

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.

66fastback · 05-25-1999, 01:47 AM

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.

jknapek · 05-25-1999, 07:02 AM

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

Diesel Dave · 05-25-1999, 04:11 PM

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

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

jknapek · 05-26-1999, 12:28 PM

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

66fastback · 05-27-1999, 01:42 AM

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)

BTW--I have better low end torque than before too.

Scooter · 05-28-1999, 07:02 PM

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

patman · 06-01-1999, 02:33 PM

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.

05-23-1999, 09:42 PM	#1
sweet65stang Registered Member Join Date: May 1999 Location: Denison,Tx.US Posts: 2	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? ------------------ JASON HIBERD

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05-24-1999, 01:46 AM	#2
66fastback Registered Member Join Date: Mar 1999 Location: Dallas, TX Posts: 208	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.

05-24-1999, 02:55 PM	#3
MUSTANGROB Registered Member Join Date: Jan 1999 Location: CHARLOTTE, NC, USA Posts: 25	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.

05-25-1999, 01:47 AM	#4
66fastback Registered Member Join Date: Mar 1999 Location: Dallas, TX Posts: 208	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.

05-25-1999, 07:02 AM	#5
jknapek Registered Member Join Date: Oct 1998 Location: Taylor, Texas, USA Posts: 10	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

05-25-1999, 04:11 PM	#6
Diesel Dave Registered Member Join Date: May 1999 Location: Martinez, California,USofA Posts: 223	Hey don't you have to change the intake manifold with a 351W head swap? Old gray brain matter straining again. ------------------ Dave Folk, '87GN, '84GT, '79 T/A 6.6 convertable

05-26-1999, 12:28 PM	#7
jknapek Registered Member Join Date: Oct 1998 Location: Taylor, Texas, USA Posts: 10	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

05-27-1999, 01:42 AM	#8
66fastback Registered Member Join Date: Mar 1999 Location: Dallas, TX Posts: 208	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) BTW--I have better low end torque than before too.

05-28-1999, 07:02 PM	#9
Scooter Registered Member Join Date: May 1999 Location: Ramsey, MN - USA Posts: 52	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

06-01-1999, 02:33 PM	#10
patman Registered Member Join Date: Feb 1999 Posts: 29	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.