Getting close to putting my motor together, and after spending a small fortune in machine work and parts, I'm undecided on using a set of stock heads or spending the money on an aftermarket aluminum set. Anyway, it's going in a model T coupe, original steel, basically a light weight car. The engine has been bored, stock crank, lake headers, comp mutha thumper cam, two carb with original Fenton manifold. I'm guessing with stock heads, maybe I'll have around 130hp. The question I have is , if I spring for a set of Offenhauser , Sharp, or Navarro heads, with the combo I have, would it be possible to gain 10-15 hp? Also, I'm wondering of the 3, which one should I choose? I realize the limitations of a flathead, and am using one for nostalgic reasons, but I'm starting to think I've got a somewhat of a performance flatly, and it might be a mistake to stay with the stock heads. Any and all imput will be appreciated. Thanks, Ed Sent from my iPad using The H.A.M.B. mobile app
My dad has a Fenton 2x2 manifold with Navarro heads and a Isky 400 jr cam on a '52 Merc block and runs down the highway just fine.
I'm pondering exactly the same thing. I have a 8ba with essentially the same setup and wondering if I should spring for the aftermarket heads. A bunch of my friends tell me the stockers will run better on a mild motor. Less RPM, more torque. Who knows? I think mine will look cooler with the stock heads. Will you really notice any difference so I'd go with the look you want.
you really have to check around. I have read that most of the aftermarket aluminum heads are no better than the stock iron ford head. the best of the stock ford heads seem to be the EAB heads used on the 53, and maybe the 52 fords. All of the Merc. heads have lower compression ratios
On my roadster I went through the same thought process. I read all I could but ended up going through John Lawson's "Flathead Facts" book with real world dynos and decided on my pair of 221 heads for my 59A Canadian motor. I'm very happy with the build but.........there is no bling to a pair of 221 stock heads painted green!.........but, I prefer performance over bling!......and, I save a bunch of money. Good luck with your decision.
According to Roadrunner Eng. Albuquerque N.M. who has flowed and evaluated many heads there is NOT 3-5 horsepower gained between stock cast iron Henry heads and ANY aluminum head made by anyone. He(Joe Abbin) is an engineer with a flow bench and a dyno with 50 years experience. His 34 Ford makes 335 h.p. With a small b & m blower and he uses FORD/MERC cast iron heads on this engine that has run 12's at over 105 mph.
For real hot setups, I would us Baron heads. They are real racer heads and I noticed several land speed cars equipped with them. No nostalgia, but good power.
Thanks for all the response, really helped to calm me down on parting with $700 for a set of heads that look nice, but so far, it seems like not much of a performance gain. Have no intention of racing this car, but I do appreciate performance improvements on a motor. Even if they were capable of an extra 10-15 hp, $700 is a lot of money for a couple heads with no valves, springs, rocker, etc. I’ll take a few photos in a few weeks and post em. Hard to make a t coupe look as cool as an A, but I’m pretty happy with how it’s turning out. Old school home built for sure, and I don’t have the talent that a lot of you guys have, but I am having fun! Sent from my iPad using H.A.M.B.
If you want a good looking set of original heads. Spend some time and refinish the surface and have them powder coated. Really makes them stand tall.
I love the look of stock heads. Here are mine getting all cleaned up. Sent from my iPhone using The H.A.M.B. mobile app
Take a set of stock heads and mill them to get .045 - .050 over the piston and you'll have an unbeatable combo.
That head looks great. I've been polishing on mine for a weeks spare time now. What are you using to grind/polish? I have mine to about 320 now. Not sure how smooth they need to be.
Mine are going to be painted so I am smoothing them up so a couple coats of primer will make them look pretty damn good. Definitely not perfect Starting with 80 grit, stones, and die grinders. I will finish them with glass bead blasting before primer just to even them up and give them a nice tooth for primer Sent from my iPhone using H.A.M.B.
I say spring for the aluminum high compression heads. I have a set of 9.25 to 1 weiand heads on mine and it runs great but I now have to run 93 octain gas.
To my understanding the only benefit of the $700 heads are for cooling purposes, not performance. Sent from my iPhone using H.A.M.B.
It's all about the preparation of the heads. Heads, by their nature are mass produced items. The head manufacturer does not know if your block is decked or not, what kind of pistons you have, or a number of other factors. Because of this, the heads are manufactured with generous clearances that are not optimized for maximum performance and econmy. The key to performance (and economy) on a flathead are compression and squish. I have found that if you get the squish (clearance over the piston) right, the compression will follow. you should shoot for a consistent .050-.060" clearance between the top of the piston and the combustion chamber in the head. This will promote turbulence and result in a better running engine. You can get the proper compression and squish on stock or aftermarket heads; it just takes a little work. I am just finishing my second set of heads since last summer. The first thing I do is bolt the head on using a used gasket with some tin foil balls stuck on the piston tops using grease. I then turn the engine over a couple of times. Then you remove the heads and check the clearances that you are starting with. For both stock and aftermarket heads, this is far from ideal. Here is a crappy cell phone picture of how I started on one head yesterday. Then you use a caliper to measure the thickness of the compressed foil balss to establish where you are at. Remember, you are shooting for .050-.060 clearance. Generally, when you check the foil balls on the valves, you will find you have enough clearance so you can concentrate on the pistons. (Sometimes the heads also need to be clearanced for valve clearance, but that's only for radical cams.) Anyway you will probably find the existing clearance is quite a bit more than you are shooting for, which will require a trip to the machine shop to bring the heads close. Ideally, you want the heads milled enough to bring the closest clearance to a bit less than .050. The next step is to bolt the heads on with no gasket. Then turn the engine over by hand. you may find the crank shaft will stop because a piston is hitting the head. Find out where the interference occurs, and grind a little bit of the head away there. After a couple of times, you will find the piston will clear, and you can go on to the next one. After 8 sessions of this, you will have an engine that turns over with the pistons just barely clearing the heads. Reassemble the engine and torque the heads down. A compressed gasket is usually .052-.058", so there you have the proper squish. How do you find where the points of interference are? Coat the top of the piston with grease and turn the engine over until it stops. Some grease will transfer to the head, showing where the interference is. I usually circle the area with a marker, wipe off the grease and grind. Take off only a little bit at a time; I have had the heads on and off 20-30 times doing one cylinder. Most will take less them that, and some will clear as is. This technique works with stock or aftermarket aluminum heads, it's just a little more work grinding cast iron rather than aluminum. There are some folks out there who shoot for .040-.050" clearance, but they are (or can afford access to) professional machinists with the proper tools and equipment. I give myself .010" leeway because I'm an amateur working in a home shop. As to heads, I'm and 8BA guy and prefer Edmunds finned aluminum heads. They have the advantage of having the spark plug relocated from stock just far enough so it's not over the exhaust valve. This allows the use of extended tip plugs to get the spark out where it can do the most good. Thus endeth the tutorial on flathead cylinder heads for today.
There's some truth to this... But the main performance benefit was increased compression. Sometimes at the expense of flow... Also guys seemed to experiment with spark plug placement and chamber design, which under certain circumstances, messed up performance... Navarro is probably about the best compromise (If they're still machined like Barney did?), Edelbrock, Evans and Cyclone are good too... I mean they're basically all good, and they're all only going to work as well as the rest of the engine is designed... I'm pretty much convinced the best combo for a street flathead is stock heads clearanced for bigger valves and something like a Isky Max-1 cam, with a blower... More stability (gasket blowout), better flow, marginally less cooling but better heat retention and fewer 'hot spots'... But the bling of a nice set of polished finned heads is cool too. Always remember... It's a flathead. Enjoy for what it is...
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