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ChadS
12-06-2006 10:22:28
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Re: 560 carb (chads) in reply to stock560, 12-05-2006 20:01:01
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The proceedure is pretty much the same,,, but there is a difference in the 4 cyl bowls and the 6 cyl bowls,,,, its mainly the metering stem. Its a larger stem, so it lets more fuel in without modifying the stem,, mostly is opening up the main jet enough to almost flood the engine just like what 460/560 mentioned. I know on my 460H, I had to go up 10 bit sizes just to get even close to that stage with a manual main load adjustment. BUUUUT,,,,, ,,, Before you go building the carb,,,, go thru and modify the governor first. I useds the combine governor housing which is a single arm governor, the tractors had a 2 lever setup with a spring, the guts are from a C-200 IH gas engine. The weights are smaller so its just like machining off the material on the combine/tractor weights. made a world of difference in the throttle responce and low end power cause that carb is open to what ever position I hold it to. Once the governor is built, move to the ignition,,, put in lighter springs in the mechanical advance (located under the points plate) in the distributor. Fix whatever you find wrong in this area, cause they are usually broke, or stuck, or just floating around loose in there, which can affect timing, it wont be steady, it will be erratic. Pull the cap off and snap the rotor with your hand,,, if its loose or dont return from full advance, back to the stop,,, somethings wrong!! Lighter springs in the advance will help even more with throttle responce and thru out the power band of the engine. Stiffer governor spring is a must, just tune the rpm to whatever you want to run. On the venturi size,,,, just depends on what rpm range you choose,,,, The big 35 is perfect for high rpm (3000 and up) but can suffer on the low end torque when it drops below 2500rpm,,, a 33 or even a 29 will help low end torque, and still be able to rev it up a bit and not lose so much low end power. I chose a #27 in my carb,,,, on the dyno, its where I found the best 540 HP, and best low end power when its lugged way down. But, I got a 263,,, if it was a 301, I may use a 29 or a 33, I run about 3200 max,,, Once the carb is rejetted bigger, you will find that it will start alot easier with out choking it so hard,,, Run good gas!!!! high octane,,, minimum of 93. Chad
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