Hey guys, I just bought a 1986 Mustang GT Convertible, fuel injected. A friend of mine had told me that in order to make a "Boss 302" engine, you needed to get a set of 351 heads? I'm assuming the heads would be from a windsor, not a cleveland, right? And also, does it matter what year engine the heads came off of? What can I expect to pay for these, is it worth it? What else will I have to do to make this work? How much will it affect performance? How much will it affect gas mileage? Thanks in advance guys...and girls.
< Message edited by scbmx87 -- 3/16/2007 1:04:01 PM >
Misinformation. The heads off a older 351 will net you a lot more then the stock E6 heads the 86's had. The problem is that the 86's also had flat top pistons and you most likely would end up with piston-valve clearance issues. The heads would indeed be from a windsor although you can use cleveland heads but need a special intake to mate up to them. Any year would work but older heads are less restrictive then newer heads. A Boss mustang had a different block that made it stronger then the standard 302 engine block (thicker walls 4 bolt mains) that's what made it a Boss, not the heads.
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Joined: 12/19/2006 From: Citrus County, FL Status: offline
wow theres a whole lot more misinformation. the only thing accurate is the fact that the boss blocks were 4 bolt mains.
Unless your 86 has E6SE heads (which i dont know that mustangs ever used) your heads would be either D8OE's (junk) E5AE's (junk, virtually the same head as the D8), or the E5TE's (which are the same as E7's...decent heads, only because of a smaller chamber size)
The only older Windsor heads that would flow any better are the 1969 and 1970 351w heads, which have larger intake ports and 1.84 intake valves instead of 1.78's. These are VERY similar to the early 90's GT-40 heads in HP gains, not to be confused with the GT-40P's which are even better.
The BOSS 302 block was a 4 bolt main block, and had screw in freeze plugs.
the BOSS 302 heads were basicilly modified 351 Cleveland 4v (4 barrel) heads. they have HUGE intake ports, HUGE valves, and small chambers. dont confuse these with Cleveland 2v heads (which are the same as 351/400M heads) which had smaller ports and valves, and a larger chamber. Also there is an Australian version, which has the smaller 2v ports and the smaller 4v chamber. these are generally considered the best heads to use for a BOSS build (or clevor as they are called) because even the 2v heads flow ALOT better than any ford Windsor head. Basically the 4v heads was overkill for a 302, and didnt make power until very high RPM's.
By looking at a set of Cleveland heads, you would never think they would fit a Windsor block but they bolt right on. Getting the water passages and such to align isnt as easy. you will need to block certain ports on the head, and drill a few new holes in the deck surface of the head and block if memory serves.
Intakes are hard to find, but they do exist in both single plane and dual plane. they also made intakes to use these cleveland heads on 351w motors, which gives you access to build some BADASS 400+ cubic inch "clevor" stroker motors
Note the Cleveland 4v / BOSS 302 Heads HUGE ports, valves and small chamber size...... BTW these are on ebay with a day left and the current bid is $585.00 and would still take some customizing (or more $$$ to be more precise) to properly work on a 302/351w
Now, lets look at some Cleve 2v heads for comparison.....
holes in the block get drilled here....
and the heads get fixed up to work on the Windsor blocks like so.....
and you need an intake like this....
yes, building a stroker w motor with aftermarket heads is cheap and easy but honestly, what fun is that? and yeah.... 4v cleve heads outperform virtually all aftermarket w heads and have canted valve angles which is a natural advantage to making more HP.
finding a middle ground is the best route for most people.... check out THESE aftermarket Aussie style Cleveland heads...
they flow 330cfm intake and 221cfm exhaust out of the box
< Message edited by my77stang -- 3/16/2007 3:00:10 PM >
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Joined: 1/9/2006 From: Puerto Rico Status: offline
Original 302 Boss engines, like mentioned above, used a stronger windsor style block, but used wide, large port Cleveland style 4V heads with poly angle, semi-hemi style valve placement.....or a "Clevor" setup, as known nowadays.........
Based on the aftermarket cylinder head options available nowadays, is not worth the investment......a 347 stroker setup + aftermarket windsor style heads (Canfield, AFR, TFS, etc) + a custom cam is a less expensive option and will give better results.....
the 302 boss had 4 bolt mains and the screw in freeze plugs like said above. yes you can make your 302 block a newer style boss by putting 351C 4v heads NOT windsor heads. only thing is you have to drill new water passeges. and if you have never done block work you should not try it yourself send the motor and heads out to a machine shop and let them do the work. you will make some crazy power with the 351C heads the new gt40 and gt40p heads were modled after them and to this day are still some of the best flowing heads out there
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Joined: 12/19/2006 From: Citrus County, FL Status: offline
quote:
I had E6 heads off my 86. D8OE's were on the 351's. Maybe the engines I looked at were all screwed up.
then yours were the E6SE heads..... swirl chambered heads that ford only used for one year. (i had a set on a 302 in my II before)
the 302's and 351's used the D8OE's from 1978 until 1985, then E5AE's on cars and E5TE on trucks. Again, the E5AE's are the same as D8OE's and the E5TE's are the same as E7TE's. The only differance between D8/E5AE and the E7/E5TE is the chamber size, with the E7's being smaller for higher compression. In 1987 they used the E7's on all 302's and 351's. the E6SE was only used on the 302's and only in 1986, during 1986 the 351's would have had E5 heads, or D8 heads (if they were using up stock of D8's)
You saying the heads were the same, then you say they are different in the same sentence so yes your a confusing person. The OP doesn't really care about the casting #'s,or the difference in E6, E5, D8 ect heads. He wanted to know if putting heads off a 351 would make his 302 a boss. I tried to explain it simply without the technical babble that a non gearhead would stumble over.
wow theres a whole lot more misinformation. the only thing accurate is the fact that the boss blocks were 4 bolt mains.
Unless your 86 has E6SE heads (which i dont know that mustangs ever used) your heads would be either D8OE's (junk) E5AE's (junk, virtually the same head as the D8), or the E5TE's (which are the same as E7's...decent heads, only because of a smaller chamber size)
The only older Windsor heads that would flow any better are the 1969 and 1970 351w heads, which have larger intake ports and 1.84 intake valves instead of 1.78's. These are VERY similar to the early 90's GT-40 heads in HP gains, not to be confused with the GT-40P's which are even better.
The BOSS 302 block was a 4 bolt main block, and had screw in freeze plugs.
the BOSS 302 heads were basicilly modified 351 Cleveland 4v (4 barrel) heads. they have HUGE intake ports, HUGE valves, and small chambers. dont confuse these with Cleveland 2v heads (which are the same as 351/400M heads) which had smaller ports and valves, and a larger chamber. Also there is an Australian version, which has the smaller 2v ports and the smaller 4v chamber. these are generally considered the best heads to use for a BOSS build (or clevor as they are called) because even the 2v heads flow ALOT better than any ford Windsor head. Basically the 4v heads was overkill for a 302, and didnt make power until very high RPM's.
By looking at a set of Cleveland heads, you would never think they would fit a Windsor block but they bolt right on. Getting the water passages and such to align isnt as easy. you will need to block certain ports on the head, and drill a few new holes in the deck surface of the head and block if memory serves.
Intakes are hard to find, but they do exist in both single plane and dual plane. they also made intakes to use these cleveland heads on 351w motors, which gives you access to build some BADASS 400+ cubic inch "clevor" stroker motors
Note the Cleveland 4v / BOSS 302 Heads HUGE ports, valves and small chamber size...... BTW these are on ebay with a day left and the current bid is $585.00 and would still take some customizing (or more $$$ to be more precise) to properly work on a 302/351w
Now, lets look at some Cleve 2v heads for comparison.....
holes in the block get drilled here....
and the heads get fixed up to work on the Windsor blocks like so.....
and you need an intake like this....
yes, building a stroker w motor with aftermarket heads is cheap and easy but honestly, what fun is that? and yeah.... 4v cleve heads outperform virtually all aftermarket w heads and have canted valve angles which is a natural advantage to making more HP.
finding a middle ground is the best route for most people.... check out THESE aftermarket Aussie style Cleveland heads...
they flow 330cfm intake and 221cfm exhaust out of the box
Wow, i feel like I just read an encyclopedia!!! Thanks guys!!!
Printable Version
"Boss 302"Help!!! - 
