Sorry, guys, but I have spent all morning searching this forum and having no joy.

Does anyone have the stock (baseline) curves on the 4.9 EFI engine? At this point I am not interested in performance options, or even high RPMs. It is first and foremost a truck engine, I want to see what sort of torque it makes from "clutch-in" RPM (about 600 RPM) through the operating range (maybe 3,000 RPM.)

These curves are commonly used on heavy-duty trucks to specify transmissions, rear end ratios, and tire size.

 

https://www.ford-trucks.com/forums/s...t=torque+curve
here's a start....https://www.ford-trucks.com/forums/s...t=torque+curve
here's another.

 

Thank you - I found those threads already. Unless I missed something, there is only one curve presented, and it is the assumed flywheel output of a computer program, starting at 2,000 RPM.

How do you know if your truck will even start the load?

 

a lower gear in the rear with the lowest gear in the transmission would presume that your rpms go higher before initial movement, so maybe you'd see 1600 rpm at that point. However, I can't find torque curves anywhere either, and my Chiltons only shows base figures at 1600-2000 rpm. Taking into consideration these engines were put in trucks up to the F600 range must mean something about the initial torque from zero. But probably means more emphasis on the gearing.

 

Likely you are correct, but I do not want to have to slip the clutch to start a load - nor to race my engine on a wet boat ramp.

Clutch in torque is not a problem with a torque converter and an automatic tranny, but is with a standard, especially if you use the M5OD or any of the 3 speeds.

I am replacing a 390 FE with a EFI 300/ 4 speed, and never had a problem with spinning my wheels nor did I need to slip my clutch (with the 390). I would like to see how the EFI 300 compares.

 

wow, looked at the boat in your gallery. I see your concern now. FWIW the efi's lost a little torque but gained a few hp when they switched to efi. Maybe switching to a centerforce II clutch may take some of the worry away. But, I'd love to see a torque curve too. This will be the first year with my 300 powered 79 bronco pushing snow. I had a 66 bronco w/170cid and 4.11 gears and dana 20 tcase that couldn't spin a tire no matter how hard I tried, but it sure pushed snow.
PS: that 390fe will be hard to beat for torque. But I understand with today's gas prices.

 

Well, in truth, I am downsizing everything, including the boat. Even stepped up on plain it burns about 15 gallons an hour - and marine gas is half again what road gas is.

I expect we will see $4 gas - so it is downsize or stay home for me!