The Ford Barn - View Single Post - Normal compression on a T... high altitude makes a difference?

40 Deluxe · 01-26-2016, 05:52 PM

Rule of thumb is a 3% horsepower loss for every 1000 ft. gain in altitude so if you are at approx. 8,000 ft. you are down to about 15 HP, maybe less. A high compression head probably won't add 7 HP at your altitude; maybe more like 5. So the head will give you back what was lost to altitude, putting you around the original 20-22 HP. That's about a 25% increase. That's a lot!

01-26-2016, 05:52 PM	#17
40 Deluxe Senior Member Join Date: May 2010 Location: now Kuna, Idaho Posts: 3,790	Re: Normal compression on a T... high altitude makes a difference? Rule of thumb is a 3% horsepower loss for every 1000 ft. gain in altitude so if you are at approx. 8,000 ft. you are down to about 15 HP, maybe less. A high compression head probably won't add 7 HP at your altitude; maybe more like 5. So the head will give you back what was lost to altitude, putting you around the original 20-22 HP. That's about a 25% increase. That's a lot!