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Discussion Starter #1
I have a 67 coupe w/ a 289. I'm planning on bolting on a set of 69 351w heads that have been mildly ported and polished. Will these heads lower my compression ratio? If so will it be so much that it offsets any power gain from increased airflow? Other than getiing a new intake are there any other compatibility issues or problems i might run into along the way? Thanks.
 

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My understanding is that you will get bigger intake valves and have better breathing (for upper RPM performance). The downside "is lower compression" but everything else will fit the same. You should get a good breating manifold (upper RPM) to match the heads. I'd go single plane but it would depend on how much your compression drops.

Also, I have also been told that a set of 289 heads with oversized valves and some mild exhaust porting are just as good if not better (because of the higher compression).

Just my 2 cents....Greg.
 
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Discussion Starter #3
FORD USED TO MAKE A KIT TO DO THE SWAP BACK IN THE 70`S AND IT INCL GASKITS AND HEAD BOLTS,
[IT COULD HAVE BEEN HEAD BOLT WASHERS] 351 HEAD BOLTS ARE NOT THE SAME AS 289 BOLTS,
INTAKE GASKIT NO BIG DEAL,JUST USE 302/289 GASKITS,IF YOUR HEADS ARE THE CLOSED CHAMBER TYPE
YOU WOULD BE FINE COMP RAITO WISE,IF THERE THE OPEN CHAMBER TYPE IS NOT WORTH THE WORK,IT WILL DROP THE COMP
JUST FYI
DAVE
 
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Discussion Starter #4
FYI, YOU CANT RUN A 351 INT IN THE SWAP,WONT FIT,YOUD HAVE TO RUN 289/302 INTAKE
 

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yah you need shoulder bolts or collars or something because the head bolts are bigger in a 351w.

For an intake just use the 289 intake or an aftermarket 289/302/5.0 intake.
 

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I think TrickFlow makes a bushing set to run the smaller 289 head bolts with one of their heads (that's tapped for the bigger 351 bolts). Probably pricey, but it might be worth a look....I would think it would also work with stock 351 heads.

Shane
 

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If you have an OEM A-code 289, your ratio shouldn't drop below 9:1, which is perfectly acceptable and shouldn't compromise the net effect of adding the W heads.

I would caution, with a lower CR, about running too much duration/overlap in selecting a cam; the resultant reversion can more markedly affect low-end torque than in an engine with a higher CR, all else being equal.

As was mentioned, a stock or aftermarket intake for a 289/302 will work fine. Port matching is nice but not absolutely necessary. Recommendation will depend on cam choice, drivetrain specs, and use. No-brainer choice would be Edelbrock Performer or, for a vintage flair, old F4B or Cobra manifold.

IIRC, your '67 heads had rail rockers so those will transfer to the W heads, if you haven't modified for studs/guide plates...

Use new 289/302 head bolts and hard washers (under the bolt heads) for low-buck clamping of the W heads. There are more expensive solutions but I've never had any problem with this one..

IIRC, as long as you retain all the early bracketry, accessories should bolt up.....my cars are pretty bare-bones so a second opinion may be in order..*G*

Any other recommendations would require more info on the engine...

Good luck!
 
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Discussion Starter #8
The engine is a stock C code. My plans were to go w/ the ported 351 heads, a cam w/ around 221 intake duration w/ 108 degrees lobe seperation, a rpm performer and a 600 cfm carb. Will i have to have the 351 heads milled to make this combination work?
 

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Hopefully, you'll get more opinions, but, with a C-code engine, which has a 9.3:1 CR stock, you'll end up in the high 8's if you're lucky, and that camshaft, with 221 degrees @ .050" lifter rise and a tight lobe seperation, is going to give you a fair amount of reversion.

As a comparison, on the true W in the race car, I run a SVO A333 cam, which has 224 IN and 234 exhaust, but, most importantly, has a CR of 12.48:1...

IMO, to run the combo you've described, in a street car, you'll need a 10" converter and a 3.89 or 4.11 gear to get the best performance/driveability compromise.

Milling heads to raise compression is a time-honored modification, but, given the chamber size and shape of the W heads, I calculated that approximately .18 cc would be reduced for every .005 removed from the surface, on average.
Typically, W heads range from 58 to 61 cc (if early heads) and 289 heads range in the 54 to 56 cc area.....so, to duplicate the early heads, a fair amount of material would have to be removed, which would open a whole can of worms regarding alignment and deck strength.

You can run this combo with listed cam, but it'll be a bit mushy on the bottom end unless you're running a manual trans or looser converter, along with more rear end gear.

Hope that helps!
 

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Pat is right on about the CR with the combination you are using. Look at the chart below and get an idea. These figures are for stanard bore motors.

Personal experience; all other things being equal, you will make more low and mid-range power with the early small chamber heads and some 1.84/1.54 valves. Do a little home porting and gasket matching and you're good to go.

http://a8.cpimg.com/image/8C/CA/10870668-f374-020000CD-.jpg
 
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