SoCal Jet Boats
Tech Talk => Engine Mechanical / Electrical => Topic started by: thewedge on May 03, 2018, 02:00:07 PM
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I just got my 454 machined . Nothing radical; pistons .030 over, crank .010 under, new rings, bearings, etc. I was running a 750 Holley vac. secondarys. So i decided to go bigger with the fuel system and bought a tunnel ram with a set up for two carbs. My dilemma is the carbs. I was thinking two 650 Holleys., but I don't know if you should run vacuum secondaries or mechanical secondaries or if even matters. I haven't chosen a cam yet because I wanted to get the tunnel ram first. Any help from you guys would be very much appreciated.
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I'd look for a set of 660 center squirters, have them done by a reputal carb shop and don't look back, they were designed for tunnel rams
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The previous writer is correct, get the 660 center squirters, and dyno the engine to get the setup right.
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The 660 center squirters are good carbs, I too have a BBC engine in my jet boat designed and built by me, I have two Holley 4160 600cfm vacuum secondary’s on my Edelbrock tunnel ram, and they work fantastic. They both have the Quickfuel Technology billet metering plates on the secondary side that house Holley jets so you can be in control of your secondary fuel curve. I had also linked the secondary vacuum canisters together so they will open at the same rate as manifold vacuum drops. I dyno tuned this engine with O2’s and EGT’s in every primary tube and staggered the jets per what we saw exiting each cylinder. This has been a very reliable set up and never has had any miss under any throttle angle.