We're racing in a sportsman class that requires factory cast iron heads and meeting a 17" vacuum requirement. So far we are running an Edelbrock Performer intake with a Quadrajet sitting on top and open long-tube headers. Other than these mods everything is stock. So far meeting vacuum isn't an issue but we are wanting to maybe step up a notch with a new cam, lifters, rockers, valves, etc. I was planning on some mild porting of the heads, primarily removing the thermactor humps and other flashing and such...nothing major. The idea is to keep the runners and such smallish to help maintain vacuum at idle but still help things breathe easier on the upper end of our spectrum (5500rpm). That was the plans, but now I have the inexpensive, possibly free option of some '66 289 heads. From what I can tell valve-size and flow numbers are just as good as my more modern 351w heads but the gain as I see it, will come in the form of smaller combustion chambers, raising our compression ratio (inadvertently helping with vacuum as well). This motor is being built for midrange power and torque, never to be ran ovre 5500rpm so bigger valves, extensive headwork, and super high-flow numbers aren't really needed I am thinking. Considering we were going to rebuild our current heads with new parts, can you confirm my thoughts on the 289 heads being a better option, maybe? Is my thinkin' here so far out of whack my wife needs to slap me and bring me back to reality?
As I recall, you will need to drill out the headbolt holes as the 351 bolts are larger than the 289's. Don
Yes Don you are correct, thanks. Hardened valve seats a must? This engine will probably not see over 50 miles each year and get refreshed during the long winters here in Wyoming
Are you running 351 heads on a 289/302 motor now, or is it actually a 351? There's two, maybe three issues; the 289 heads can bump compression up by a bunch if swapping onto a 351 (beyond pump gas depending on the heads), and the head bolt holes have to be drilled to 1/2". There's also considerable difference in intake port sizes, the intake may not match up too well... If the motor has OEM dished pistons, a switch to flattops will do the same thing with less mods...
Crazy Steve, thanks for the heads up here. It is a 351w motor. I was going to just work on the stock heads and leave it at that but then the option for the 289 heads has presented itself. I had not considered the port size difference this is something I will be looking into immediately. As far as pump gas goes I have the option of running higher octane av-gas or race fuel as well. Just looking to get the maximum performance here with cast iron stuff.
One other thing not mentioned... what year is the motor? Ford switched to 302 head castings on the 351 in '77 (factory drilled for the 1/2" head bolts) and dished the pistons even more, so the early heads may not even offer a compression increase.
Just got some pics of the 289 heads. While I cannot see it in the pics he says the numbers stamped are C80E. Ok, it seems the more I read and rely on the internet here the more I get confused. Here are some pics of the heads in question. Can you help me identify them maybe? He says the stamping is C80E which to me says '68 but then there is that big bold 66 right there on the head staring at me. I'm lost LOL
Been there, done that. It really pumped up a 351. We had to use a cast iron manifold and a 2 barrel carb. 1971, the early days of the 351W, it was difficult to find a 4 barrel cast iron intake. We borrowed one to dyno test and found out that the 2 barrel carb worked better with the 2 barrel manifold than it did with the 4 barrel intake and an adapter. You need the 289 intake gaskets for the heads to intake and 351 for the front and rear intake to block or use silicone because the 351 block is wider. I seem to recall there's something different in the way the manifold bolts on too. I think the 351 push rods worked with the adjustable rockers on the heads.
Ok having looked at these pics on my computer now instead of my old POS flip phone I am thinking they are indeed '66 289 heads C6OE not C8OE casting. This also leads me to believe they have 54cc chambers, and 1.78/1.45 valves. My current heads are the same for valves but Ford claims 64cc on the combustion chambers (E7TE).
Just a standard '66 289 head (C6OE), nothin' special.... If your current heads have pedestal or rail rocker arms, you'll have to switch to hardened pushrods and non-rail rockers.
Check the chamber volume. The 66 might be a casting number for the upper half of the mold that they didn't change if they changed the lower half and chamber volume.
That should bump your compression about 1 point. Be careful about valve spring pressure, those press-in studs can pull out. Generally, these are replaced with screw-in studs for reliability.
We raced under stock head casting rules for years. No aftermarket heads allowed but you could port. We always used 64-66 289 heads on 351W. It really helps compression. We played with several different sized valves and ended up using Chevy 1.94/1.60 valves. Anything bigger won't increase flow because of the small ports. Even if you port until you hit air, any bigger valves won't help. We ported to match the biggest 289 intake gasket we could fine (Fel Pro), ported to the biggest exhaust gasket we could find with the small Ford bolt pattern on it (Mr Gasket, picture of exhaust port below ), switched to screw in studs and guide plates, drilled the head bolt holes and opened up the pushrod slots so the guide plates were controlling instead of the head slots. We also decked the heads a bunch to up compression. With a 2 notch flat top piston you can get to around 11.25:1. The only advantage of the 69-70 351W head is you don't have to drill the bolt holes. You don't gain as much compression. Still have a set of done heads sitting on a complete engine after we quit racing. Exact same setup. SPark
Hey thanks to all for your generous input here, it is very appreciated. Due to financial reasons we are going to have to run our factory E7TE heads. Will do some minor intake port work but planning on spending most my time on the exhaust ports. Limited in RPMs by my intake and other things so I am thinkin' we should be fine with this approach for this year. Thanks again... Chuck
Top end lubricant, like Bardahl will suffice in place of hardened seats. @ 50 miles a year it will take lots of years worth of bardahl or even more expensive additives to pay for hard seats. Pocket port the heads or buy some templates and template port them. A motor that never sees more the 55 hundred shouldn't need much of a cam shaft so vacuum should not be a problem to maintain. Keep you compression up and everything well sealed and you should be golden.
A Clevor would be the cat's a$$. Closed chamber factory iron Cleveland 4V heads on a Windsor block. A cam with good lift but smaller duration would keep the vacuum up and still move a TON of air through them. I ran a true Cleveland engine with stock cc 4V's on a 393ci stroked bottom end in my OT stang for a few years before going to a big block Ford. In front of a top loader, it spun effortlessly to 7250 rpm and pulled hard right up to redline. What a hard running, fun car to bang gears in. Just a thought. You can grab them on the web for pretty cheap.
As-cast, the 289 heads will outperform the E7s. The 289 heads do have a smaller chamber (because of the 289's smaller bore) but if your class allows decking a factory head, then this is a non-issue. The E7s allow you to run a factory type hydraulic roller cam without a lot of modifications but I'm not sure if you are planning to do that anyway. Both of these heads are terrible in regards to exhaust flow so you'll want to concentrate any porting efforts there. Your best bet with the restrictions you outlined is to locate a set of GT40 heads from an Explorer. They flow much better than either of the heads you have, and a pair can be found on craigslist or a junkyard for about a hundred bucks. Some of them have an angled spark plug which may interfere with your headers or exhaust manifolds so keep an eye on that. Valve springs were WEAK on these the day they were new, so budget for a new set to work with your cam. Here's a flow testing comparison among several factory castings, both stock and ported. Good luck! https://www.fordmuscle.com/archives/2000/05/heads/index1.php PS - Cleveland heads perform great on a 289/302/351w block, but you're getting into a somewhat exotic combo there. It's pretty common for sportsman classes to outlaw Clevors, so check first before building one.
You are right, I brain farted. The 289 has a shorter stroke, therefore a smaller chamber is needed to keep the compression the same.
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