High compression heads - Worth it?

[wensum]

I am running a 7:1 head along with many other mods and the power to cruise up hills is fantastic for a car of that age. I do get a small improvement in economy and despite having a non-standard exhaust system, it still sounds like a Model A and idles like one too

[Synchro909]

When I bought my first Model A, I hadn't driven one before. I asked a friend who had been driving one for years to drive mine and tell me what he thought of it. I had fitted a 5.5:1 head. He couldn't believe the grunt mine had. He then put one on his car and was DELIGHTED when he didn't have to change down on the hill near his house.
There are several benefits to fitting a HC head, most of which have already been mentioned above so I won't restate them. If you are thinking of fitting one yourself, you may not notice much difference on your first drive, or the second but one day, you'll notice how hills that caused you a problem just aren't there any more and standard cars are in your rear vision mirror.

[denniskliesen]

If you look at Piriano's Model A charts, notice the horsepower torque gain when a cast iron header was added.

[Terry, NJ]

To add to H.L.'s post, It's exactly as he says, water, gas , Etc flow through a smooth pipe faster than a rough or irregular one. In a mod. A s case it's worse, the intake runner is cast too small! I drill mine out with an 1 1/4 drill and polish it out to 1.281 +.010. Then, with a long polishing mandrel, I polish as far back up into the manifold as the curves allow, matching the ports to a gasket. On the block. Put an old gasket on the bolts and with a pencil, make an outline of the stock to be removed and proceed to remove it, rechecking the pattern several times. This improves the alignment between the ports in the block and the manifold (Henry, like most builders at the time, paid little attention to port alignment and interior finish and just sent them out in "as cast" condition) Make these small improvements and you will have some (Minor) improvement.
Terry

[Mike V. Florida]

Originally Posted by ursus

Not apparently mentioned yet is that a high compression head will result in improved combustion efficiency hence better gas mileage.

I have found this to be true, add cooled temps as well.

[H. L. Chauvin]

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Also FWIW:

I would imagine that different engine re-builders could have different observations and opinions to offer in different ways; however, Mr. Ron Kelley once told me that every time he gets an engine to rebuild with beat up Babbitt, he immediately asks the owner about his Model A timing procedure and his spark lever location while driving.

In many cases, he commented, that it was not the Hi-Compression head's fault, but the Model A owner's timing was too far advanced for his constant hill country driving or too far advanced where the owner is constantly floor boarding the accelerator on take off.

When one hears engine pinging/knocking when the engine is straining, this is not much different than a Model A owner hitting the top of his/her pistons with the brute force of a 50 pound maul ............ thus smashing soft Babbitt metal material further down below.

[barkleydave]

My engine is strong but working harder than I liked in hill country. Well now have Snyder HC head and just completed a tour on the Blue Ridge Parkway. MUCH better low end torque and made the run up to 6,000 ft very enjoyable. I am not an engine rebuilder or a hot rod tinkerer so this was the most effective change without disturbing what already was a good running truck. The HP 5-1 head is very popular with touring groups.

Even with all the high climbing gas mpg was 15.5

[smittykid]

I have 3 Model A's with the HC head. To me, there is a noticeable difference in climbing hills with the HC heads. Not really any faster, but long steep hills in 3rd gear are not a problem. I just had Ant. Engine Rebuilding redo the short block on my 29 Tudor and I added a Snyder's 5.5 to 1 HC head. I had my Grandson who is a tool and die maker check the Snyder's head for any warpage or twisting. It checked out fine-no milling needed. I really don't notice any change in the engine sound with the HC head.

[duke36]

Well stated by others; those folks primarily in higher altitudes with "leaner" air benefit from higher compression heads, etc.

[old31]

Originally Posted by Terry, NJ

To add to H.L.'s post, It's exactly as he says, water, gas , Etc flow through a smooth pipe faster than a rough or irregular one. In a mod. A s case it's worse, the intake runner is cast too small! I drill mine out with an 1 1/4 drill and polish it out to 1.281 +.010. Then, with a long polishing mandrel, I polish as far back up into the manifold as the curves allow, matching the ports to a gasket. On the block. Put an old gasket on the bolts and with a pencil, make an outline of the stock to be removed and proceed to remove it, rechecking the pattern several times. This improves the alignment between the ports in the block and the manifold (Henry, like most builders at the time, paid little attention to port alignment and interior finish and just sent them out in "as cast" condition) Make these small improvements and you will have some (Minor) improvement.
Terry

Terry, could you post pictures of the tools that you used and mention where you bought them?