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Discussion Starter · #1 ·
Can anyone give me any info on whether or not Heads/valves from a 1969 351W engine will work on a 302 HO out of an 86 Mustang?

I understand ford did away with the wedge-shaped heads on that particular year of 302's for emissions purposes. I was told that this swap would work but am unsure of where to research to make sure before i bother starting on the swap.

Thx,

Ron
 

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hmm....i dont think so..i believe the 86 has weird notched pistons or sumthin like that....but im not sure...the good engine guys will know lol
 

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From what i understand 302 and 351w heads are interchangeable. For instance you could take AFR 185 heads off a 5.0L and put them on a windsor 5.8L. But be sure to check the piston to valve clearance. However this swap will not work whenever a 351C is involved. What I want to know is why not take the 5.8L block and swap it for the 5.0L?:scratchchin
 

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if you do use the 69 heads,,,have hardened valve seats installed,they were set up for leaded fuel....
 

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Also those heads we're probably not emossions legal.
 

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The heads will fit with a couple of cautions. the old 351 use a 1/2 head bolt. The newer 302's used a 7/16" head bolt. You can buy bushings from Edelbrock to make up the differance

The valves are small enough to not be a big issue, depending on what your cam is.

Some '69 heads have a thermacter boss in the exhaust port. You can grind that out to improve port flow.

Hardened valve seats are a must with unleaded fuel.

Watch your compression. The '69 351W have bigger chambers than previous windsors. But probably smaller than '86 heads. Depending on cam and altitude, it might be an issue.

Those heads also used a rail type rocker arm. If you want to use an aftermarket rocker arm, you'll need to switch to studs and guide plates.
 

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Discussion Starter · #7 ·
Ok, so what I'm seeing is that it's going to be somewhat of a pain. The reasoning for doing the swap of only the heads is that that is what i have, not the entire engine from the old 69 ford. I understand that in 1986 Ford changed the heads to give a larger combustion chamber and smaller intake and exhaust ports (better emissions?...less HP ) and i had been told that on those 69 Windsors it was about the exact opposite.

The engine in my 86 Mustang is completely stock except for aftermarket headers. Here soon I am pulling the engine/tranny from the vehicle and putting it into another 86 Mustang GT w/ T-tops that i got from Nevada that does not have cancer(rust) like mine does. While i have the engine out i figure it would be an excellent time to do some toying with it. Emissions is not much of a concern since i live in Nebraska and i havent seen a vehicle inspection in 20 years here, although I have heard they still do them on spot checks.

I guess the question becomes (assuming the swap will work with a certain amount of modifications) is there any point to it? With a somewhat minimal investment other than time, is there likely to be an improvement in HP from doing this swap? or better off saving the money and buying new heads from say Edelbrock or Ford Racing?
 

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Bolting on the heads is rather painless... You're going to run into trouble with piston to valve clearance though. The '86 HO is the only year Mustang to use pure flat top pistons with NO valve reliefs.

If you use anything other than TW's or the crappy factory '86 head, you're almost certainly going to have to notch the pistons.
 

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I guess the question becomes (assuming the swap will work with a certain amount of modifications) is there any point to it? With a somewhat minimal investment other than time, is there likely to be an improvement in HP from doing this swap? or better off saving the money and buying new heads from say Edelbrock or Ford Racing?
Since you already have the heads, I'd say, yeah it's worth it. You'll spend a couple hundred bux making the swap. Probably about $1K less than new alum heads.

You'll flow more air, and probably raise the compression. I think the '86 heads have about a 65-68cc chamber. The '86 heads also have a heart shaped chamber for emissions.

I'd do it.
 

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You'd be strongly advised to check piston to valve interference, those 1986 pistons are the problem with no valve reliefs. You can get an Isky Cams piston notching tool and make some. Then you just get some head bolt bushings from Edelbrock or TFS and they'll go right on.
 

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Discussion Starter · #11 ·
It has also been suggested to me that when i do this swap in a few months that it is time to change from the stock intake manifold and at least do the MAF switch, and possibly a new larger throttle body.

The way I understand, these heads are going to allow more exhaust flow, so that being said, I am going to want less restricted intake in order to really feel the most effect of doing this swap. Also, these heads were taken off the engine several years ago and have been sitting in a garage. I would imagine I'll need to take them to a machine shop to have them "rebuilt" before putting them in, so anything else that I should have them do at the shop with them? I really dont much care for the idea of having someone at a shop telling me what he thinks, as i have a large chip on my shoulder for mechanics out to make a buck.
 

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When they redo them, have a 3 angle valvejob done, the valves lapped, and decked to make sure the deck is flat. If you want porting or polishing, have that done too.
 
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