Why no just go with a TH 400.
That's with 3.42's? I believe the rear in the car is currently 3.73 but I don't want to re gear the 8.5 that's going in it if I don't have to. Lower the RPM on the highway the better in my opinion.W/ 28's @3000 you would be going 73mph the 4L80E would have you @2250
What does that have to do with choosing a 4L80e over a TH400 as you suggest? They have identical gearing 1-3 so I don't see what point you're trying to make.Sounds like you want a racing engine and try using it on the street. Your whole set up has to complement each other for what you want to do. I'm afraid your not going to be smiling much.
the problem is the more aggressive of an engine you build, aggressive cam,rage runner head, single plane intake, etc the less an engine likes to lug around at low rpm. All those pieces are mean to horsepower aka high air flow seeing as hp is torque times rpm divided by 5252. You don’t tend to use those parts to make torque monsters that make power in the lower rpm range. Why? All about airflow dynamics. If you’re cruising at 15% throttle and 2k rpm your engine will use the same amount of air no matter how big or small your heads intake cam etc are. However the bigger the ports the slower the air speed becomes which is especially important with a Carb’d engine because you need air speed in order to keep the fuel suspended in the air and into the cylinder. Even with port injection you still want good velocity in order to have consistent air charge in the cylinder. This is part of why people run higher stall converters with built engines like this even if only on the street so it isn’t lugging the engine all the time. Lower rpm the better for cruising isn’t always accurate, a real bad example but I’ve got a 94 ranger with a 4.0 and that thing absolutely loves cruising at 2800-3000 rpm. Most diesels like around 2000 rpm because they effectively make torque at low rpm. Some engines idle at 8-900 others have to be at 14-1500 to over come the drawbacks of making higher rpm power. Where your idle cruise rpm will be is decided on your combination, not what you think you want.What does that have to do with choosing a 4L80e over a TH400 as you suggest? They have identical gearing 1-3 so I don't see what point you're trying to make.
If it's that the engine will be out of it's powerband at 2000-2500 rpm going down the highway... I look at it this way, it's still 406 cubic inches, by default it's going to be way more torquey than any 305 that came in these cars in front of a 700R4 or 2004R, and they have absolutely no problem going down the highway at relatively low RPM.
Is my logic flawed?
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