MTFCA Forum

Wanted to Buy - An R G Reeder Aluminum Low Head or more information on why no one is selling the low head. Jim Golden

What I really wanted was more information on why the Low Heads have never been reproduced in aluminum.

So far, I have only been SCAMMED by two individuals, one in Texas and one in Pensacola, Florida!

Jim, I feel your pain also, as I too need a Low (hi-compression) Head for a current project. I hate to butcher a firewall just to run one of the high ones being offered.

BRENT in 10-uh-C wrote: ↑

Wed Sep 24, 2025 3:55 pm

Jim, I feel your pain also, as I too need a Low (hi-compression) Head for a current project. I hate to butcher a firewall just to run one of the high ones being offered.

Maybe this helps.
I am running a low head, milled 1/8" with hi dome pistons. Performs well with 95# compression.

speedytinc wrote: ↑

Wed Sep 24, 2025 4:11 pm

Maybe this helps.
I am running a low head, milled 1/8" with hi dome pistons. Performs well with 95# compression.

I may have to do that ...but I likely will give up 4-5 horsepower.

If you think about it, the difference between a high and low head, from a functional standpoint, is the size of the water jacket/cooling passages. As your engine produces more power, it has more heat to get rid of, so a high head makes more sense from a reliability perspective. That's probably why you don't see as many aftermarket high-compression low heads.

Keep crankin',
Eric

J1MGOLDEN wrote: ↑

Wed Sep 24, 2025 3:41 pm

What I really wanted was more information on why the Low Heads have never been reproduced in aluminum.

So far, I have only been SCAMMED by two individuals, one in Texas and one in Pensacola, Florida!

Jim, I live in Texas, and you weren't scammed by ME. You turned down my offer. I am offended you would say I scammed you.

ewdysar wrote: ↑

Wed Sep 24, 2025 5:18 pm

If you think about it, the difference between a high and low head, from a functional standpoint, is the size of the water jacket/cooling passages. As your engine produces more power, it has more heat to get rid of, so a high head makes more sense from a reliability perspective. That's probably why you don't see as many aftermarket high-compression low heads.

Keep crankin',
Eric

I think the point is to have an early engine head that looks original, but performs better. That was my thinking for my 14.
A Prus head would be a better option, but it don't look stock/correct in a brass T.

Terry, you are not the guilty party in Texas, but I was surprised there were more Jason Moores than John Smiths in Texas.

ewdysar wrote: ↑

Wed Sep 24, 2025 5:18 pm

If you think about it, the difference between a high and low head, from a functional standpoint, is the size of the water jacket/cooling passages. As your engine produces more power, it has more heat to get rid of, so a high head makes more sense from a reliability perspective. That's probably why you don't see as many aftermarket high-compression low heads.

Keep crankin',
Eric

Eric. in theory that might seem believable, but it is the Radiator that changes the coolant's temperature, -not the quantity of coolant. If the Radiator cannot dissipate the coolant's heat, then the coolant in a head with more coolant capacity just continues to see the temps match the same as a head with a smaller capacity.

Jim: PM sent . Bruce

BRENT in 10-uh-C wrote: ↑

Thu Sep 25, 2025 12:05 pm

ewdysar wrote: ↑

Wed Sep 24, 2025 5:18 pm

If you think about it, the difference between a high and low head, from a functional standpoint, is the size of the water jacket/cooling passages. As your engine produces more power, it has more heat to get rid of, so a high head makes more sense from a reliability perspective. That's probably why you don't see as many aftermarket high-compression low heads.

Keep crankin',
Eric

Eric. in theory that might seem believable, but it is the Radiator that changes the coolant's temperature, -not the quantity of coolant. If the Radiator cannot dissipate the coolant's heat, then the coolant in a head with more coolant capacity just continues to see the temps match the same as a head with a smaller capacity.

Ok, Brent, I agree that the radiator is the part that reduces coolant temperature, but the engine also changes the coolant temperature. I also agree that a small increase on the total volume of coolant is irrelevant in this conversation. We all know that when a radiator’s ability to transfer coolant heat to the outside air is compromised, the engine can overheat, i.e. loose fins, crud in the tubes, etc. The other half of the process relies on the block, hoses, and head’s ability to transfer combustion heat out of the iron and into the coolant that is on its way to the radiator. If there are restrictions to coolant flow in the engine, i.e. collapsed hoses, crud in the block, smaller coolant passages, etc., then the engine may overheat, regardless of how well the radiator works. I posit that the high head transfers heat into the coolant better/flows better than a low head. I guess the real question is: why did Henry change to the high head?

Eric

Eric,
IIRC, the lower compression high head was in response to the low quality, lower octane gasoline that was available at the time.
Keith

So are we saying that they couldn't lower the compression using the low head casting? It seems to me that they didn't need to add that much extra material to the head just to lower the compression, simply adding 1/8" to the block side of the casting (adds 22cc/cylinder) would lower the compression enough for bad fuel, more than the difference between low and high heads. Perhaps the lower compression combustion chamber was incidental to the larger water jacket. I personally believe that the larger water jacket improved flow, which in turn, made cylinder temperatures more even from front to back.

Bringing this back to the original question, why aren't there many aftermarket high-compression low heads, I think that the basic "high" design manages heat better and is therefore better suited for running a Model T at higher output levels than originally designed.

Apparently, the cost to build a casting mold is much larger than the market that would be willing to buy one of those heads.

James, you have a good point. Approximately 2 million T’s were delivered with low heads, more than 13 million with high heads. Since these aftermarket heads were sold as “bolt on” upgrades, high heads are a direct replacement for 85% of Model T’s made.

Personally, I think that it’s easier to fit a low head into a high head car than a high head into a low head car (as noted early in this thread), but the 85% “no additional modifications needed” audience is where a maker should obviously focus.

I still wonder if Ford documented their reasoning for increasing the water jacket size with the “new” high head design. Were they addressing a known issue with an improved component, or was it merely easier, faster, cheaper to make?

Keep crankin’,
Eric

I have one that will be going to Hershey next week has never been bolted on light pole 41 or c4I 29-32

I will also have a Giant Power cast iron head that has been magged and milled same place.