Maximum RPM for 273 64 Dart
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Here's a dyno of a stock commando, makes peak power at 5100 rpm there would be little reason to go to far past 5000-5500 rpm, or less if valve float is happening.
Edit" for some reason I thought your post said you had a commando
Edit" for some reason I thought your post said you had a commando
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Even though it’ll spin higher than where it makes reasonable power, the oiling system may not be able to adequately supply oil past 6500.
Stock I agree with 5-5500 redline if a new engine. All depends on the cam profile and valve springs.
You may find that it runs out of making power at 4400 to 4800 anything above may not give you anymore.
What is in the 273? Where is your oil pressure?
If factory stock 2 barrel 4,200 rpm, 4 barrel 5,200 rpm. I see no reason to run an engine past peak horse power. Another rule of thumb is 1 psi of oil pressure you need for every 100 rpm. so at 6,500 rpm you should have approximately 65 psi of oil pressure. The crank, rods, pistons, and valvetrain on a 273 will easily live to 6,500 rpm if set up right. You can also do power loops on a quarter mile looking at mph. Shift at the rpm that runs the highest mph with that set up. No reason to run to 6,000 rpm if it runs the same mph as it does at 4,000 rpm. 340 oiling add ons will give a bit of insurance. Windage tray and a high pressure oil pump relief spring, (45 psi to 65 psi)
Just run it till it blows and build another one and don't spin it that high.
clifftt
Well-Known Member
273: Cool chart! Factory rated was 230 for a stock Commando as I recall, you're just passed that. You dyno'd a stock motor to get these numbers?Here's a dyno of a stock commando, makes peak power at 5100 rpm there would be little reason to go to far past 5000-5500 rpm, or less if valve float is happening.
Edit" for some reason I thought your post said you had a commando
View attachment 1716099097
If you like that one here's a dyno of an engine masters competition 273 making 473 hp @ 7900 rpm. Done by some of the members think Hemirunner/IQ52.
If I remember right it's sleeved and bored to 3.75, ported indy x heads and 250 ish cam.
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Actually (and I apologize for this quibble), but the factory rating was 235. Not that those old gross horsepower ratings were that accurate anyway. Or that production standards weren't sloppy enough that there was probably more than five hp difference between one motor and the next.
Secret to running a 273 2 barrel is
Run a lite platform like a Valient
Run some steep gear, 3.91s are a good starting point, 3.55s are a good compromise
Good camshaft is the E4 Isky grind
Change your fuel line over to 3/8”. Remove the screen filter from the fuel inlet. The stock 4 barrel is anemic so the more fuel flow the better.
Headers
work on your 60 foot times and your shift points. 273 2 barrels seem to perform well at the lower RPMs. Get it in high gear as soon as you can.
Low 14s are common with those combinations.
Good example is Paul Wong who runs division 7, home track is Vegas. He runs a Stock Eliminator A body wagon and is consistent in the mid to low 14s
Google him
Run a lite platform like a Valient
Run some steep gear, 3.91s are a good starting point, 3.55s are a good compromise
Good camshaft is the E4 Isky grind
Change your fuel line over to 3/8”. Remove the screen filter from the fuel inlet. The stock 4 barrel is anemic so the more fuel flow the better.
Headers
work on your 60 foot times and your shift points. 273 2 barrels seem to perform well at the lower RPMs. Get it in high gear as soon as you can.
Low 14s are common with those combinations.
Good example is Paul Wong who runs division 7, home track is Vegas. He runs a Stock Eliminator A body wagon and is consistent in the mid to low 14s
Google him
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