I ran 781's for years with good success as quick as 6.0's in the 1/8, 10.0's in the 1/4 mile, all motor. They were costly though with around $1200 in the assembled heads with good stainless valves, springs, titanium retainers, good 3 angle competition valve job, bowl blending and port matching the intake opening.
Looking back, I would have been better off saving a few more $$$ and getting something like the Brodix Race Rite ovals which are a much better head.
If rectangular, you need to stay below a 320cc head for sure.
Also, figure on a converter in the 5500-6000 rpm range for optimal performance.
Looking back, I would have been better off saving a few more $$$ and getting something like the Brodix Race Rite ovals which are a much better head.
If rectangular, you need to stay below a 320cc head for sure.
Also, figure on a converter in the 5500-6000 rpm range for optimal performance.