351w heads

Discussion in '1974 - 1978 Mustang II Talk & Tech' started by 1WildII, Oct 24, 2007.


  1. 1WildII

    1WildII Member

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    I just got a set of 351w heads and I want to put them on my 302, I got everything but valves and basically this is the first motor I will be building (so im green, dont laugh) but I need a shopping list, the 302 is pretty fresh so I dont need to do a full rebuild or get to crazy, but I was hoping for some cam suggestions and valve suggestions also anything I might be forgetting. A friend of mine just gave these heads to me, supposadly they are good to go on but they are in pieces, I got brand new roller rockers he gave me, valave springs, pushrods, retainers, studs etc... just everything but guides lifters and valves. I just dont want to go buy random parts without getting some info from people who know what they are talking about, kind of afraid of putting a valve through a piston or something lame like that. Any help on this subject would be appreciated.

    Chris
  2. $50COBRAII

    $50COBRAII New Member

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    Chris, first off make sure what year the heads are. Around 1977 Ford started making the ports and valve sizes the same as the 302. If i remember correctly they also went to the bolt down rocker arm at the same time. 69/70 was the best of the Windsor heads. In any case good or bad you will need the aftermarket washers that let you use the 7/16 headbolts with the Windsor heads or drill and tap the block for 1/2 bolts. If this is wrong i'm sure someone will chime in shortly:)
  3. itsaMustangtoo

    itsaMustangtoo New Member

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    1st- like $50cobraII stated- check the heads, if not 69/70 with the bigger valves, forget it. 2nd Keep the valvetrain the same brand( ie: crane, comp, ford motorsport etc.) this means cam, rockers ,lifters,locks,etc. As far as a cam suggestion a 280 degree dur. with under 500" of lift is a fine street cam with a very mild idle. 3rd and probably the most important, go to your local ford dealer and get the motorsport pushrods for the swap ( .090 over I think) It has been some time since I swapped a set on my 289. If not available scour the summit site. That is where I found the 7.00 pushrods for my latest project .
  4. 1WildII

    1WildII Member

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    thanks for the help so far. I'll check the year on those heads tonight, but basically what youre saying is if they aren't 69/70, its not worth it?
  5. THE COBRAMAN

    THE COBRAMAN pig 'rassler Founding Member

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    77-up 351 heads are the same as the 77 up 302 heads aside from the bolt holes. 69cc and went down to 1.78/1.45 valves (same as 302 valves)

    69-76 351 heads actually have larger chambers than the same generation 302 heads at 60.4cc, but do have the larger valves 1.84/1.54

    Unless you have the stock 77-78 shortblock, there's no real advantage to going to 351 heads. You'll actually lose a little compression on the earlier engines. The pre-77 351 heads will raise compression on the 77-78 to about 9.1 compared to the 8.4 with the OE head. IF it's the late 69cc head, compression on the 77-78 remains at 8.4, falls to 7.2 on the 75-76 302. This is based on the OE style piston.
  6. a351Must2

    a351Must2 Windsor II Founding Member

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    ARP makes a set of head bolts that have the 7/16" 302 thread size with a 1/2" shank to bolt 351W heads or aftermarket aluminum heads to the 302.

    The chart I have shows the following:
    69-74 C90E-B,D; D0OE-C,G; D0OZ-C; 60.4cc, 1.84/1.54 valves
    75-77 D5TE-EB; same size as previous, but has air injection ports in the exhaust side that restrict flow a little (die grinder and a carbide bit can fix it).

    78 will have pedestal mount rockers, 69cc combustion chambers, and the 302 sized valves (1.78/1.45)

    The swap would definately only be worth it if you have 69-77 351W heads, and the '77-'78 302 block.

    ...and if I'd read cobraman's post, I'd realize I'm restating the same things he'd just said...
  7. 1WildII

    1WildII Member

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    The heads are 69, C90E, the block is a '74
  8. 1WildII

    1WildII Member

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    so with the 69 heads and 77 block its worth it, will it be worth it to put them on my 74 302?
  9. $50COBRAII

    $50COBRAII New Member

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    Dont forget

    If the heads need a valve job you can have them milled at the same time, that would help compression.
  10. Blue Thunder

    Blue Thunder Active Member

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    1969 - 1974 are the only years that the 351W has bigger valves and ports than the 302. (Castings C9, D0, D1, D2, D3, D4)
    Your compression ratio will drop, too, so the power you gain from the improved flow may be offset by the power(and efficiency) you lose by lowering the compression. You can angle mill the heads to drop the combustion chamber volume, but if you mill them too far, the intake manifold will need to be milled to match. Also, milling the heads moves them closer to the pistons, so valve clearance may become an issue, (remember, the piston valve reliefs are machined to fit 302 valves, not the larger 351W valves) as well as pushrod length.
  11. Turbo II

    Turbo II Founding Member

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    Sounds exactly like the combination I'll be running. Dropped my '74 block off with my engine builder a while back and told him "you're the expert, build me a reliable set-up with around 300HP" We will be using a set of '69 351W heads (ported and polished) with roller rockers and Comp Cams' Magnum 280H shaft. My builder is going to be milling the block 10 thou and the heads 40 thou and matching the intake. I'm no engine expert so I'll have to trust him (which I do), he's a Ford guy from way back and has a very good reputation locally, unlike 90% of the rest of them. Some real horror stories out there!

    Francis
  12. Dano78

    Dano78 Founding Member

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    The '69 351W heads you have are good heads. I believe they are adjustable rockers and not torque down -(look adjustable but aren't --5/16" fine thread studs) rockers. You also notice that you 'll have extra intake bolt holes if you try to run the 302 intake. Some guys leave 'em, some plug the holes, and some grind out the bosses in the water passages slightly increasing waterflow. It's up to you, how you want to deal with it. Seen it work all 3 ways.

    As far as a cam- Here's the specs I've been using on several street builds I've done in the past

    Lift- .472/.496
    Dur@.050 214*/224*
    Lobe center 112* (110* is ok too)
    Intake Cntrline 108* (110* is ok too)
    (using a 110 spec will make the cam a tiny bit more lumpy and take away a tiny bit from the bottom end but add to the top end, a 106 on the Intake will definately make for a little lumpier sounding cam)

    Use a cam ground with either a 302 or 351W firing order. I like the sound of the 351W (302HO) Firing order and is also said to pick up a few ponies too.

    Staying under .500 lift should keep you safe and not have to worry about smacking pistons on most builds with flattop or stock pistons. Also very friendly with compresson ratios 9.0 or lower. You start to loose streetability when you move your duration up higher than 228* thus requiring a looser converter and better rear gearing not to mention a better exh system (headers) to actually benefit from the duration above 228*. Dual pattern cams (like the specs I suggested) seem to work really well on the street and especailly in the small Fords. Single pattern cams work fine, but have a narrow powerband and just don't pull as hard off the line and through the powerband like a dual pattern does... that is unless you have alot of worked-over speed parts bolted on, gears, stall conv., and so on.

    Keep the cam and lifters of same manufacture if at all possible.

    That '74 block is kind of a turd because it's the 1st casting of the 'tall deck' blocks. in '78 they went back to the shorter deck. The taller deck will add .020 to .030 (depending on the piston that was used) extra depth to the piston down-in-bore measurement, over a short deck 289/302. This drops your compression ratio a point or so over using the short deck block.

    The absolute WORST factory 302 was the '77. It was fitted with the "turd-of-all-time" 69cc cyl heads thus cranking out just barely over an 8:1 C/R... :notnice: The return of the shorter deck in '78 combined with these boat-anchor 69cc heads didn't make it as bad, but still isn't worth shouting about.

    You'll be right around 8.7:1 with the 351W heads and the '74 block.

    Pushrods..... my experience... the last thing to buy. Due to different base circle measurements, swapping heads, aftermarket rocker arms, etc.. pushrods are usually bought last because you'll have to assemble the engine and correctly measure for the correct length that you'll need. Yeah sure you can thrown in any old set that is close and it will run, but it could cause you further problems or damages later on down the road... trust me, I know. Again, the cam specs I suggested, seem to work fine with a stock set of rods as long as the base circle of the aftermarket cam is the same as a stocker.

    Alot of the engines I have built are "Heinz 57" and as long as you pay attention to what you are doing and making good measurements, you'll be just fine.

    Hope I haven't overloaded you with info, just my experiences. Hope this helps out a bit. :nice:
  13. Blue Thunder

    Blue Thunder Active Member

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    I never knew the 74 302 block had a taller deck, or I wouldve used one. Taller deck = more room for longer stroke & longer rods. ha
  14. Dano78

    Dano78 Founding Member

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    Yeah i didn't realize it either until i opened one up. I have yet to see a '73 casting block, but all the '72 and older blocks I've ran across have been short decks. I've found a couple '72 blocks in '73 cars, so Ford may have not casted any '73 dated blocks at all. And oddly of all the Windsor SBF was the only engine to recieve deck height adjustments. None of the BBFs, Clevelands, Modifieds, or FEs ever had any changes like this.

    Then what's really weird in '74 - '76, the block being a tall deck, but they dumped on a set of 58cc heads!?!
    Then '77, same tall block, now 69cc heads...
    and then in '78 they shortened the deck back to '72 spec and left the 69cc heads on...!?!

    And the point of this was....? :stupid:

    Deck Heights-
    221-255-260-289-302 = 8.206
    '74-'77 302 = 8.229
    '69-73 351W = 9.480
    '74-up 351W = 9.503

    I have a feeling ford engineering was doing more experimenting with combustion space in their BONG than effective use of combustion space in their engines....:D

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