Long Rod 376” Engine
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Long Rod 376” Engine Thinking about what to build for my next engine and I decided I want to build a 376 with a stock crank and 4.065 pistons out of a 6.0L block, Im wondering if anyone has done something with a 6.275 rod in with a shorter compression height on the piston, 1.165 CH piston and figuring out the CH I would need for 0 deck would be 1.154 by my math, so I would just need a thicker head gasket. My main question is has anyone done something like this but rebushed the rod for the smaller .927 pin on the pistons? I can only find a piston that fits the bore and dome I want that has a .927 pin, and they only make 6.275” rods with a .945 pin. Has anyone done something like this?
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From: Texas
Piston accelerates faster with a short rod.
I wish you luck on this, but I doubt you'd see much difference on a dyno compared to a standard length rod. I think there are definitely easier ways to squeeze power out of one of these things.
I wish you luck on this, but I doubt you'd see much difference on a dyno compared to a standard length rod. I think there are definitely easier ways to squeeze power out of one of these things.
Coming from the endurance engine world, I can tell you with assurance that long rod engines are built with durability in mind. It’s much easier on skirts, and reduces cylinder wall temps somewhat, depending on actual rod angle of course. Piston speed away from TDC is reduced because of this which means the piston dome is in the upper part of the cylinder longer, which can help the engine ingest the air/fuel charge a bit longer. On the flip side, as the dome speed is slower on the exhaust stroke coming up from BDC, it can hamper exhaust scavenging, because exhaust gases are going to be moving slower up the port initially. You have to work with your camshaft designer at length with a long…er rod build to take advantage of the pluses and overcome the cons of a long rod build. In the endurance engine world, the lower friction in the bottom of the cylinder caused by the better rod angle, was our major focus. At engine speeds above 8k, friction is a major player because it’s a heat source and kills reliability exponentially. Cylinder finish and shape is magnified. Keeping oil on the skirts is paramount. Pushing the piston pin upward makes ringland design tougher, but with todays ultra thin ring sets available and corresponding small diameter wrist pins, it’s manageable.
Having said all this, in a street build, a long rod engine sounds cool to talk about at car shows, but that’s about it. You’ll find no advantage whatsoever ever unless you’re located in the western part of the country, and you’re doing multi mile runs at 150 mph and keeping it up at 7k+ for extended periods of time.
Having said all this, in a street build, a long rod engine sounds cool to talk about at car shows, but that’s about it. You’ll find no advantage whatsoever ever unless you’re located in the western part of the country, and you’re doing multi mile runs at 150 mph and keeping it up at 7k+ for extended periods of time.
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Thread Starter
Teching In
Joined: Jan 2025
Posts: 4
Likes: 0
Coming from the endurance engine world, I can tell you with assurance that long rod engines are built with durability in mind. It’s much easier on skirts, and reduces cylinder wall temps somewhat, depending on actual rod angle of course. Piston speed away from TDC is reduced because of this which means the piston dome is in the upper part of the cylinder longer, which can help the engine ingest the air/fuel charge a bit longer. On the flip side, as the dome speed is slower on the exhaust stroke coming up from BDC, it can hamper exhaust scavenging, because exhaust gases are going to be moving slower up the port initially. You have to work with your camshaft designer at length with a long…er rod build to take advantage of the pluses and overcome the cons of a long rod build. In the endurance engine world, the lower friction in the bottom of the cylinder caused by the better rod angle, was our major focus. At engine speeds above 8k, friction is a major player because it’s a heat source and kills reliability exponentially. Cylinder finish and shape is magnified. Keeping oil on the skirts is paramount. Pushing the piston pin upward makes ringland design tougher, but with todays ultra thin ring sets available and corresponding small diameter wrist pins, it’s manageable.
Having said all this, in a street build, a long rod engine sounds cool to talk about at car shows, but that’s about it. You’ll find no advantage whatsoever ever unless you’re located in the western part of the country, and you’re doing multi mile runs at 150 mph and keeping it up at 7k+ for extended periods of time.
Having said all this, in a street build, a long rod engine sounds cool to talk about at car shows, but that’s about it. You’ll find no advantage whatsoever ever unless you’re located in the western part of the country, and you’re doing multi mile runs at 150 mph and keeping it up at 7k+ for extended periods of time.
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