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Discussion Starter #1
I have a 302 currently in my 84 mustang. I also have a 351. I have no idea if it is a windsor or a Cleveland or a modified. I heard about the way to tell if its a windsor or cleveland by if it is a windsor it will have 5 bolt pattern on the valve cover and an 8 if its cleveland. How do i tell if its a modified? And what i thought about doing is taking the heads off the 302 and intake and put it on the 351 block. I was told this will work. I just want to know if its true and how to identify what 351 i have and if this will work will it work with only one kind of 351 or any of the three.
 

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The valve cover idea is correct with the exception that 302/351w has 6 valve cover bolts. A 351w would look similar to your 302 just a bit physically larger, a 351M or 351C are a physically different engine family with many differences between them.
 

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302/351W will have the thermostat housing on the front of the intake..
351C will have the thermostat housing coming off the top of the timing cover.
351M is very similar to cleveland but look for about a 1 inch tall ridge beside the thermostat housing...
 

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Discussion Starter #4
i looked at the 351 yesterday and im pretty sure its a windsor. will the heads and intake from my 302 fit on to the 351? i was told that they would but im curious to see if that is correct.
 

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Heads yes, intake no as the 351w has a roughly 1 inch taller deck height. So the 351 is not only taller, but wider as well.
 

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There are some "depends" involved here but you might want to go the other way on this by putting the 351 heads on the 302. They are interchangable and may be the better choice.

There is some work to get them to bolt on but it's minor stuff. I'm sure others will chime in on that swap. You would still use the 302 intake.

Swapping in the entire 351 is probably more work than you want due to the added width of the engine.

John
 

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Yes swapping 302 heads onto a 351 is not the way to go if your after performance...They will also need the bolt holes drilled out to fit on the 351..
 

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Discussion Starter #8
So since im going for performance should i put the 351 heads on the 302? And why is it not the best way to go by putting the 302 heads on the 351 and i dont mean by the work that needs to be done to do it i mean by the way the engine works? And what will happen if the 351 heads are on the 302?
 

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Depending on what the year of the heads are, the 351w heads have larger ports and slightly larger valves. By installing 302 heads on a 351, you are basically taking away some power.

Late model 351 heads flow the same as the 302 so if you are upgrading the heads the ones to get are the early style.... But the difference are the bolt size on a 351 windsors are 1/2" and they are 7/16 on 289/302...late model heads have 1.78 intake & 1.46 exhuast valves and early ones have 1.84 & 1.54 & also slightly larger intake and exhaust runners.

Ford began using the same basic head casting for both the 302 and 351W in 1977.

These later 351s, originally identified as 351Ks, have the rectangular 302 intake water passages and 6 intake manifold bolt holes. Original 351W heads have L-shaped water passages and 8 intake manifold bolt holes.

Also, the late model 302/351 heads have a larger water passage at the rear,
which means the intake gaskets are different between early and late models.

If you swap "real" '69-'76 351W heads onto a 302 you need to use the
351W style intake manifold gaskets, as the 302 gaskets will leak water
at the unique 351W intake manifold water ports.

I hope this helps some more
 

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I have no clue if it is an early or late 351. Overall is it beneficial to do this?
Look under the dipstick tube and tell us what code is stamped there. I would say it's only beneficial if you plan on doing a complete engine rebuild.

What I would do, would be to rebuild the 351w and put into your '84 mustang and forget about the 302. I have a 351w in my '82GT and the swap really isn't that hard.
 

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The money you would spend on making stock,iron 351W heads work is not worth it.Plus early,69/70 heads have large combustion chambers so you have lower compression.Your 84 will have NO trouble swallowing a 351W,same motor mounts,same front cover,same bell housing bolt pattern,460s fall into that engine bay and look lost!If your 302 needs a rebuild you will be money ahead rebuilding the 351W,plus there are a ton of after market headers,etc. for that swap! ROY.
 

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Discussion Starter #13 (Edited)
I will check the number by the dip stick. The only reason i asked about swapping the heads is because i was told if 302 heads were on a 351 that the compression would be boosted from like a 9:1 ratio to like a 10:1 and boost my bottom end power. But if its more benificial to just put the whole 351 in there than i mine as well but im not sure because im not going to be racing the car, its just ro drive and i want that bottom end power and wont the 302 heads do that? Because its not like im going to be driving arougun nd at high rpms all the time. The carborator i have came off a 351 but im pretty positive it is the same original carb that was used on a 302351 and it bolts up nicely to the 302 intake.
 

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Yes, you could install the 302 heads on a 351w but that doesn't make it a good idea. Yes, you might get an increase in CR but you also lose in other areas, like valve sizes and air flow. It sounds like both engines need rebuilt anyways, so just spend the cash on building the 351w. It doesn't have to be a monster 351w either. A fresh 351w will out perform that tired 302 with 351 heads slapped on!
Sell the 302 and use that little bit of money to build the 351w. It's really a no brainer as to which engine to build and drop in.
 

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Discussion Starter #15
I understand whar your saying but i want the 302 heads on the 351. More bottom end power before 4 or so rmps. Isn't that correct?
 

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Not really. You can build any engine to make power where ever you want it to be, if you select the right combination of parts. Look at my signature below. That setup has ridiculous amounts of low end torque and I did it without putting 289/302 heads on it.
Your looking for a shortcut it seems and shortcuts don't usually have happy endings in the world of engines.
 
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