Useful Formulas and pointless numbers Youre welcome!
Engine Dispacement (Cubic inches)
Bore x Bore x Stroke x .7854 x Number of pistons = Displacement
460 stock bore is 4.362 and stock stroke is 3.85
4.362 x 4.362 x 3.85 x .7854 x 8 = 460.270 CI
460 .030 over = 4.362 + .030 = 4.392 bore
4.392 x 4.392 x 3.85 x .7854 x 8 = 466.623 CI
My personal favorite:
460 .030 over with 4.5" stroke
4.392 x 4.392 x 4.50 x .7854 x 8 = 545.403 CI
Here is a formula to tell you the optimum carburator size (CFM)
(Engine CID) x (Max RPM) X Volumetric Efficiency / 3456 = CFM
Volumetric Efficiency (VE) is a function of how well the engine can use the air that is pumped in it....basically.
For a stock engine use .75
For a mild engine use .80
For a modified engine use .85
For a race engine use .90-1.00+
(466) x (5500) x .85 / 3456 = 630 CFM Is the optimum amount of air than can flow into this engine at WOT under perfect conditions. I guess I dont really need a 750
Axle shaft torque load
(Torque) x (first gear ratio) x (axle ratio) x (90% efficiency).
500 x 2.46 x 4.56 x .90 = 5047.92 Ft lbs of Torque.
This does not factor in tire size. Obviously tire size would effect axle load but anyway....
Here is what Mosers axles are rated at. (they are crap so dont buy them though)
30sp = 6200 ft lbs per axle
31sp = 7000 ft lbs
35sp = 9600 ft lbs
40sp = 12000ft lbs
U joint (size load and axle rating)
1310
Width 3.219" Cap dia 1.062" Max angle 30* Continuous ft lbs 130 Short term ft lbs 800
1330
Width 3.625" Cap dia 1.062" Max angle 20* Continuous ft lbs 150 Short term ft lbs 890
1350
Width 3.625" Cap dia 1.188 Max angle 20* Continuous ft lbs 210 Short term ft lbs 1230
1410
Width 4.188" Cap dia 1.188 Max angle 37* Continuous ft lbs 250 Short term ft lbs 1500
I want to do a front axle continuous and short term ft lbs rating but I couldnt find what I wanted. A while back someone on pirate built a machine to test the rotational "twist" break strength of several different axles and I couldnt find it. If anyone does please post it up.
Hope this helps.
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Kris
Please do not PM me. My email is STGCountryboy312 at AOL dot COM
I stand corrected, I just started looking alot down here last week and it seemed you ripped a new one in some of us newbs.But hey thats OK, we have to pay our dues. Thanks for the info. Whats your best time in the sand drags? My friend has a big block in a old bronco that sand drags and is getting beat by a 500+ CI dodge,DOT tire no paddles.
I stand corrected, I just started looking alot down here last week and it seemed you ripped a new one in some of us newbs.But hey thats OK, we have to pay our dues. Thanks for the info. Whats your best time in the sand drags? My friend has a big block in a old bronco that sand drags and is getting beat by a 500+ CI dodge,DOT tire no paddles.
.3 nanoseconds!
Are you in the right thread?
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Kris
Please do not PM me. My email is STGCountryboy312 at AOL dot COM
I got the CFM formula from 460ford.com Lets figure my 545 build
545x6200x.85/3456 = 831.06 cfm
I was told to use a 950HP on the small side and 1050 dommy on the large side.....maybe it isnt right. Scott wants me to use a 950HP with 750 venturis on my current engine. Hmmmmm.
__________________
Kris
Please do not PM me. My email is STGCountryboy312 at AOL dot COM
I re read your post and you were mud racing 200 Ft. I think he is in 300 ft, really not sand, more like clay and dirt mixed dry beside the local mudbogg pit. Lots of street trucks and a few full modified. The carb formula seems on the small side or ive always had too big of carb.
most people over carb engines on the street all the time but on a race engine you run a lot more carb. I always try to tell people they don't need a 750 on a 460 but no one believes me for some reason.
also for those that don't know there is a section of automotive calculators on FTE.
oh ok. Not really the right thread for this but since you asked.
I cant remember my exact numbers but Im usually in the 4.5-4.7sec range in 200ft and always just under or right at 50mph of forward speed on an extremely similar track. My biggest hold up from keeping me competitive is weight. Many trucks in my class dip in to the high 3s on cut up trucks. They are technically supposed to be street legal (turn signals brake lights headlights insurance and tags) but it doesnt mean they are street driven or even could be. I drive my truck to work and hunting and if I could afford the gas Id drive it pretty much anywhere I wanted. I complain all the time about it but I cant run in the stock class because I have larger than 35" tires and Im running under the 5.0 sec cutoff. I dont do it for money...just fun.
Ive always heard everyone runs a carb that is really too big.
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Kris
Please do not PM me. My email is STGCountryboy312 at AOL dot COM
another great writup Kris!!! ive read alot of your tech threads and appreciate them and the work you put into them for all of us!!!
thanks again for all the info!!!
Yukon 4340 Dana 60 35 spline short side axle...12,000 / 130
Stock Dana 60 35 spline short side axle.........8,300 / 35
Yukon 4340 Dana 44 30 spline short side axle....5,800 / 35
Stock dana 44 30 spline.........................5,000 /35
__________________
Kris
Please do not PM me. My email is STGCountryboy312 at AOL dot COM
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