[ivymike1031]

The pins are safety hold-downs. They can be used in place of, or in conjunction with, the standard hood latch. There may have been some hoods that heavy, but I've never seen one. I'd have estimated more like 50-80lbs for a heavy one. I had a '78 cherokee for a while, with a tremendous hood on it, and I could remove and install the hood myself, so it couldn't have been all that heavy.

If you had an engine that was 100% efficient, you'd get 3 to 5 times as much power out of a typical gasoline engine. You'd get about 2 to 3 times as much out of a turbocharged diesel (modern diesels are more efficient than modern gasoline engines, by 50% or so).

An example: 2000 Honda Civic Hx, 1.6L engine
displacement 1.6L
peak power 115HP @ 6000rpm
peak torque 110 FT*LBF @ 4500rpm

Torque at 6000 rpm is 100.7 ft*lbf, so let's estimate that volumetric efficiency is about 100.7/110 = 91.5% at that speed. (VE tells you how much air is getting into the engine compared to how much could get in if it were turned very slowly)

At 91.5% VE, 6000 rpm, this engine will pump about 0.481 kg/s of air through it. With an AF ratio of 14.9, the engine will use about 0.032 kg/s of fuel.

If all of that fuel is converted to mechanical energy, with no heat going out the tailpipe, no heat going out the cylinder walls, no friction losses, no pumping losses, etc., you will get about 326 hp.

This estimate gives the Honda Civic Hx engine a very high efficiency, about 35.3%, which makes me suspect I did something wrong. Perhaps I was too pessimistic about the volumetric efficiency of the intake?

If I redo the same calculation for 4500rpm (peak torque), I get the following:

the baseline engine produces 110 ft*lbf at 4500 rpm, or about 94 hp.
if I assume 100% volumetric efficiency, then I get 35.5% again. If I assume 104% v.e., I get about 33.9%. My reaction: wow, that's high.