big block tunnel ram in jet boat, need carb help

Old 04-14-2017, 04:25 PM
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tiago
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Default big block tunnel ram in jet boat, need carb help

I bought a jet boat with edelbrock street tunnel ram and 2 1850/ I guess 600 cfm carbs, vacuum secondary with side hung floats. they are old and leaking, I want to replace them but I was told by jegs to use 2 double pump carbs with center hung floats. I am concerned about washing cylinders. has comp cam 568/ 578 lift and 292/296 duration, give me some advice, thanks
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Old 04-17-2017, 05:28 PM
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Swiley383
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I have read vacuum secondary on a tunnel ram won't work right due to low vacuum. Contact Holley or Quick Fuel or some other carb manufacturer and see what they say.
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Old 04-18-2017, 09:14 PM
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mytmouz
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My old boat had twin 850's on it, and I didn't have any issues, other than keeping fuel in the tank...
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Old 02-16-2021, 09:46 PM
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lg406
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Originally Posted by Swiley383 View Post
I have read vacuum secondary on a tunnel ram won't work right due to low vacuum. Contact Holley or Quick Fuel or some other carb manufacturer and see what they say.
Not true. Manifold vacuum has nothing to do with vacuum secondary. In fact it is recomended you use VS carb on your setup. BTW: 1850 holley is a 600 cfm carb.
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Old 02-18-2021, 05:33 AM
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BigBlockMark
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I would consult a well known custom carb builder and have him spec and build you carbs. Less grief in the long run. Mark Whitener in Orlando Florida is who I recommend. Just google jmarkaudio. He also has a fuelsystems forum online. He has helped me on custom engine carbs..Prices of new Holley carbs are going up again March.
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