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Old 08-06-2014, 09:00 AM   #40
66Submarine
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Location: Dallas, GA
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Re: 4bt cummins swap

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Its more important to look at the torque vs. RPM curves here guys.
Read my post again (did you read it to begin with?).

The numbers you quote for the 292 are from the later smog era; '64-'66 made 255ftlbs of net torque and had the added power higher up that the 4BT just doesn't. Yes, the 292 makes its peak power a little higher up; that's where GM intended you to run it.

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I have a hard time believing that even with the right gearing a 292 could push this (see below) down the road at 60 MPH. (This is what I found my 4BT in on my 1947 Ford diesel 1.5 ton project... and yes I drove it home.... the 4BT in my van replaced an existing 6.2L diesel and was mated to a TH 400)
The 292 is/was a schoolbus/dump truck engine--you know that, right?

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If you've never owned/driven a diesel pickup.... your wasting your time trying to really describe... there two way different animals.
TURBO diesel. Want to race my 454 spark-knocker with your 6.2?

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Take the big brother here guys... the 6BT 12 Valve... a 190HP, 440 ft-lb ft of torque engine.
Take a 6.0L LQ9 LS engine.... same torque, twice the HP.... it should be better right?
The 12V will pull the house down over the 6.0. At a slower speed yes... but at 30,000 lbs.... 12V 6BT diesel > 6.0L LS gasser
Again, no. Wind the 6.0 up to the moon where it makes its power, and it'll out-pull the diesel. You think the diesel is more powerful because WHERE YOU ARE RUNNING IT AT IT MAKES MORE HP. And what do you mean "At a slower speed yes..."? More power=faster on the planet I'm from.

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Differentiate what they really are guys...... 4BT: A puller meant for work.. and in stock form.... a MPG sipper if you have extremely favorable highway gearing. 292: An occasional puller capable of running out empty to highway speed without any issue or concern for gearing in most platforms.
The 292 was never intended as that; it is a HD truck engine, designed for HD truck use. The (stock) 4BT is also a truck engine, but just a lamer one that is missing the entire top end of its powerband.

Just think of it this way; the 292 can spin 1,300RPM faster than a 4BT, right? So, 3,600/2,300=1.56. I'm just going to use that extra gear on this hill, and you can use that badazz 4BT grunt in high gear.

Now my 292 makes 400ftlbs @ less than 1,600RPM, and makes another 48HP @ 2,300RPM. 4BT isn't so bad anymore, is it? I can hold 3,600RPM as long as you can hold 2,300RPM.

Again, HP where you run it is what makes the truck go.
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Last edited by 66Submarine; 08-06-2014 at 09:08 AM.
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