I have a 276 desoto S-19 .40 over what would that now make it...I know not that big of a change but just curious ??? also has a racer brown cam 4x2 intake stock comp I know this made 160 hp from the factory Any idea on what kind of hp it should make now...Iam thinking close to 200
Take your bore squared (multiplied by itself) times your stroke times 0.7854 times the number of cylinders in your engine to arrive at your cubic inches (cid). Here is that formula simplified: (bore) x (bore) x (stroke) x 0.7854 x (# of cylinders) = cubic inch displacement. This, of course, requires that you know the bore and stroke of your engine. bore² x stroke x 0.7854 x 8 (cylinders) equals....... dj
uuugh, not so fast..... 276 has a bore of 3.625 291 has a bore of 3.7187 276 + 040 = 3.665 so we are along way from 290 inches. A very general rule of thumb is 10 inches for .060 overbore so you get about 5-6 new inches. 276 + 6 = 282. .
Double check what?? The bores are what the bores are...... Put some new batteries in your calculator.
hehe... So all the math formulas in the books I've studied in the last 35 years are wrong??? Gee I might as well throw them all the trash 'cause they're screwed up....
I just crunched the numbers it comes out to 290.3269051 or basically 290 CI. Now take that and add the number of shingles it takes to roof a dawg house devided by how many times Huckle Berry Finn smoked a pipe and the HP comes out to a little over what it had stock or even less depending on if the advertised HP was accurate or just a number on a page.
Yep, and they're incorrect. You couldn't know unless you had other reference sources than that one. With the stroke listed on that site, 3.44, you'd have a stock displacement of 284 CI. Bore was 3.625, as you originally stated. Stroke was 3.344, for a stock displacement of 276.1 Whoever entered the data on the hemi website missed a keystroke.
Good catch arkiehotrods, I did not pay any attention to bogus stroke number since we (I) was only dealing with the bore. If 'we' simply pay attention to the fact that there is a linear relationship between the bore and the final displacement then it is easy to see that the 290 number is suspect when compared to the 291. Another way to make a 'quick and dirty' ***essment is to use 'ratio and proportion'. .
OK so my numbers are wrong or correct given the numbers supplied. And its an Ausie dawg, some sort of a dingo lookin' thing.
I don't think 73RR was using the correct formula...he had bore from two different engines, never mentioned the stroke. The formula as published (by yours truly) is accurate, and IF YOU KNOW WHAT YOU'RE DOING and can FOLLOW SIMPLE MATH INSTRUCTIONS, then you should be able to also come up with ± 290 cu in. squaring the bore (after adding the 0.040 increase) and then multiplying by the stroke and the constant (0.7854) saves you from fiddling around with pi (3.146) to calculate the area of the piston top. All you're doing is calculating the volume of a cylinder and then multiplying it by the number thereof. dj
Going back to basics the formula for the area of a circle is Pi X R squared. Where R is the radius. (D/2) To find the volume of a cylinder just multiply by the depth of the cylinder. Then given the volume of one cylinder multiply by the number of cylinders. In this case 8. Pi is the constant which is the ratio between the diameter of any circle and its cir***ference which to 5 decimals is 3.14159. With the .040 over bore the diameter is 3.665 stroke is 3.344 Plug that into the formula you get RXR = 1.8325 X1.8325 = 3.3580 Multiply by Pi 3.3580 X3.14159 =10.5496 Multiply by depth (stroke) 3.344 = 35.2779 Multiply by number of cylinders X 8 = 282.223 ci An increase of about 6 cubic inches.
You can't avoid Pi in calculations with any circle. The constant 0.7854 you refer to here is simply Pi divided by 4. Given the formula I set out in the previous post where you have to work with the radius squared this equates to D/2 XD/2 which equals DXD/4. Any way you look at it the division by 4 must occur and whoever devised this modified formula has elected to divide Pi by 4 rather than the result of D X D. The result ultimately is the same however. The number for Pi and the basic formula I learned over 40 years ago so I find I can always do these calculations from these basic principles.
Or could do: Pi x (Bore/2)^2 x Stroke x 8 cyl = Displacement Pi=3.14159265........ ...this one's for the real nerds out there. ah...covered already by fredeuce
formula is correct, the numbers were wrong. only way a .040 over 276 comes out to 290 cubes is to stroke it a little also. they have the same stroke, you can't possible have the same displacement when even a .40 over cut still leaves you a smaller bore than the stock 291
It is good to know that math is the same in OZ as it is in Ore-Gun... Different ways maybe, but all use the same math.
It looks like 6 cubic inches is what Iam seeing .....looks like 282 is what it is. glad it didnt turn out to be 283 sounds like a chevy LOL ...Thanks people!!!
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