I’m in the midst of researching Horsepower and Torque ratings for all Box Panthers. I have stumbled upon a little bit of weird information. It seems that during the CFI years, there may have been an optional CFI 5.0L engine with more horsepower. But my two sources somewhat conflict each other. Here is what my sources say:
Source #1 – Chilton’s Auto Repair Manual
This is where I first got a little suspicious. Chilton doesn’t list any optional 5.0L engines. As I was writing down the figures, 1983 had 130 horsepower, 1984 had 140 horsepower, and 1985 had 165 horsepower. Whoa! 165 horsepower… what’s so special about 1985, other than the roller cam compatibility? I figured it had to be a misprint, they may have been using the figures from the LTD LX (Fox Platform). The VIN was F, what the Boxes have. This was not the HO engine numbers.
Source #2 – The Encyclopedia of American Cars
I first check 1985 values… 140 horsepower, which must be right, I’m thinking. I’m running on down my list, starting from the beginning checking these figures against the other book. Then, 1983. The horsepower for 1983 5.0L is listed at 130, same as the other book. And then an optional 5.0L, available across the Panther Line only (CV, GM, TC, Mark VI) with 15 more horsepower. And optional 5.0? I go on to 1984. Optional 5.0L CFI with 155 horsepower, standard on Wagons. And the same thing for 1985.
So is there any truth to this optional extra horsepower CFI thing? Anyone heard of it before? What’s the difference in the lo-po CFI 5.0 and the mo-po (more power) CFI 5.0? Maybe CFI is better than SEFI…
A couple of other interesting tidbits that cross-checked correctly:
-1990-1991 cars with the 5.0 and dual exhaust have a little extra oomph than their single exhaust counterparts. Single exhaust figures are 150hp@3200, 270ft.lbs.@ 2000. Dual exhaust figures are 160hp@3400, 280ft.lbs.@2200.
-The box with the most torque wasn’t the later model 351W. It was the 1979 351W non-CA emissions version. It pumped out 286 ft.lbs. at tractor-like 1400 rpm! Shoot, you’d be doing a burnout with just the high-idle on! I bet one of those things are a beast to drive in the rain. And BTW, it only let out 142 smogged ponies. And BTW X2, the CA version dropped almost 30 ft.lbs and pushed a whopping 138 horsepower.
- The box with the least power was the 1981 4.2L (255 cid). Based on a de-bored 302 block. Numbers were 120hp@3400, 205hp@2600. Thankfully, 1982 was the last year of the 255, but it did pick up and extra 2 horsepower and 4 ft. lbs that year.
Source #1 – Chilton’s Auto Repair Manual
This is where I first got a little suspicious. Chilton doesn’t list any optional 5.0L engines. As I was writing down the figures, 1983 had 130 horsepower, 1984 had 140 horsepower, and 1985 had 165 horsepower. Whoa! 165 horsepower… what’s so special about 1985, other than the roller cam compatibility? I figured it had to be a misprint, they may have been using the figures from the LTD LX (Fox Platform). The VIN was F, what the Boxes have. This was not the HO engine numbers.
Source #2 – The Encyclopedia of American Cars
I first check 1985 values… 140 horsepower, which must be right, I’m thinking. I’m running on down my list, starting from the beginning checking these figures against the other book. Then, 1983. The horsepower for 1983 5.0L is listed at 130, same as the other book. And then an optional 5.0L, available across the Panther Line only (CV, GM, TC, Mark VI) with 15 more horsepower. And optional 5.0? I go on to 1984. Optional 5.0L CFI with 155 horsepower, standard on Wagons. And the same thing for 1985.
So is there any truth to this optional extra horsepower CFI thing? Anyone heard of it before? What’s the difference in the lo-po CFI 5.0 and the mo-po (more power) CFI 5.0? Maybe CFI is better than SEFI…
A couple of other interesting tidbits that cross-checked correctly:
-1990-1991 cars with the 5.0 and dual exhaust have a little extra oomph than their single exhaust counterparts. Single exhaust figures are 150hp@3200, 270ft.lbs.@ 2000. Dual exhaust figures are 160hp@3400, 280ft.lbs.@2200.
-The box with the most torque wasn’t the later model 351W. It was the 1979 351W non-CA emissions version. It pumped out 286 ft.lbs. at tractor-like 1400 rpm! Shoot, you’d be doing a burnout with just the high-idle on! I bet one of those things are a beast to drive in the rain. And BTW, it only let out 142 smogged ponies. And BTW X2, the CA version dropped almost 30 ft.lbs and pushed a whopping 138 horsepower.
- The box with the least power was the 1981 4.2L (255 cid). Based on a de-bored 302 block. Numbers were 120hp@3400, 205hp@2600. Thankfully, 1982 was the last year of the 255, but it did pick up and extra 2 horsepower and 4 ft. lbs that year.
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