The Ford Barn

8EL · 12-02-2023, 09:38 AM

It is fairly simple to determine that increasing the compression ratio on the little Ford 4 cylinder A engine will make the car more drive able due to the additional power it will develop. But by how much? What are the comparisons to be made between the two aftermarket iron heads offered?

The low range torque curve for the 6.0:1 head was a little flatter than the 5.5:1 head, power output was negligible for the two, about 3.5 HP. For an engine with insert bearings and given that the cost for the two heads is the same, the 6.0:1 head would probably be the way to go.....But what of the exhaust note between the stock and higher compression heads? Are they the same?

I know that the 10.5-11.0:1 V8s from the 60s had quite distinguishable exhaust sounds over their low compression 8.75:1 counterparts. But ignition, valve timing (camshafts), carberaturion/induction, and exhaust was also different for these old fire breathing dragons.

I guess I want it to sound like a Model A, those who are using these heads, which one is it, and what does it sound like??

12-02-2023, 09:38 AM	#1
8EL Senior Member Join Date: Jul 2023 Posts: 256	5.5:1 vs 6.0:1 heads It is fairly simple to determine that increasing the compression ratio on the little Ford 4 cylinder A engine will make the car more drive able due to the additional power it will develop. But by how much? What are the comparisons to be made between the two aftermarket iron heads offered? The low range torque curve for the 6.0:1 head was a little flatter than the 5.5:1 head, power output was negligible for the two, about 3.5 HP. For an engine with insert bearings and given that the cost for the two heads is the same, the 6.0:1 head would probably be the way to go.....But what of the exhaust note between the stock and higher compression heads? Are they the same? I know that the 10.5-11.0:1 V8s from the 60s had quite distinguishable exhaust sounds over their low compression 8.75:1 counterparts. But ignition, valve timing (camshafts), carberaturion/induction, and exhaust was also different for these old fire breathing dragons. I guess I want it to sound like a Model A, those who are using these heads, which one is it, and what does it sound like??