and it worked well? my neibor said never use a vac sec carb on a jet boat. so hes full of s**t?
He's not full of it, as it will work fine.
Is it base case......Hell no!!
A single carb can be bad enough with cyl to cyl fuel distribution (especialy part throttle cruising), let alone a vac sec, they make a real mess!!
I have run a 3310 750 Holley vac secondary on my 454 BBC. My buddy gave me his 750 DP, but I could never get it to idle right. Neither could he because he replaced it with a Demon. My vac second. has been running flawless, so I don't have really any good reason to take it off. Plus I just rebuilt it too. I am not expert, but I think you should be fine running a vac sec on your 350.
I stay away from vacuum secondaries because they are 1, bad on gas mileage, 2 I like to control the throttle position of my boat, 3 distribution issues. Many people use them with good results though so its all personal decision I suppose.
thanks for all the info guys.im a pretty good carb guy,but never tried a vac.sec. on a jet boat.what jets and power valve would you suggest as a baseline? 350 chev 11:1 compression, 488I 510E 300i 310E 110LC CAM,B impeller 1400lb boat. thanks scott
The only time I tried to run one. The secondarys would try to open up just at plane then you would try to back off and the boat would come down from cruise and off plane! It would run good at WOT. Just didn't like the surging when secondarys opened!