tunnelram or not???
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tunnelram or not???

  1. #1
    Senior Member rogerroost's Avatar
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    Default tunnelram or not???

    So I bought a 76 rogers at the end of the summer,only got it out twice.has a 460 soild cam ,tunnelram 2x600's.I found it was a fight at lower -mid rpms,pull good &hard full throttle then at about 4800ish it would fall down a bit at w.o.t..If I backed off a bit the motor actually picked up a bit.
    I think the tunnalram is higher rpm range than what I want.by the way ,what I want is more pleasure,driveable,not so much race.I THINK I want to replace the tunnel with a weiend stealth ,hyd cam,maybee 850cfm.
    does this sound like I'm on the right track or am I missing something with the tunnelram setup,perhaps too big of carbs?maybe 2x400cfm .I'm confident that the motor is good about9.6:1 comp ratio,d3ve heads,roller rockers,msd,professionaly built

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    Senior Member GAWnCA's Avatar
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    Just my 2 cents, but if you are changing out the tunnel ram intake for the Weiand, I have the 8012 and topped it off with the Edlebrock 750 CFM carb. It's pretty much plug and run. This is what I have and am happy.
    Wags

  4. #3
    Is it Summer Yet?! SoCalKev's Avatar
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    Quote Originally Posted by GAWnCA View Post
    Just my 2 cents, but if you are changing out the tunnel ram intake for the Weiand, I have the 8012 and topped it off with the Edlebrock 750 CFM carb. It's pretty much plug and run. This is what I have and am happy.
    I have the same. With a Holley tho. Good IMO
    Sanger Super jet in Progress

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    Senior Member GAWnCA's Avatar
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    Too many people OVER carb their motors. I would have gone with a Holley but a racing buddy told me they need to be rebuilt often if not run all the time. I guess we all have our preferences.
    Wags

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    Senior Member chevy's Avatar
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    Could be the pump not loading any more at that higher RPM

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    Senior Member GAWnCA's Avatar
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    4800 RPM isn't very high. I'm not big on a lot of electronics. I'm of the KISS school.
    Wags

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    Is it Summer Yet?! SoCalKev's Avatar
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    Quote Originally Posted by GAWnCA View Post
    Too many people OVER carb their motors. I would have gone with a Holley but a racing buddy told me they need to be rebuilt often if not run all the time. I guess we all have our preferences.
    Power Valve Issues often. Its either ALL or nothing usually with these carbs.


    I agree with overcarbing. See how it runs with a 600-750 Single carb setup first.
    Sanger Super jet in Progress

  10. #8
    Senior Member GAWnCA's Avatar
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    For a cruiser the 600 might just be right. I maybe over carbed as well with the 750. I've got a new rebuild and until I can get some time on it, I know it'll run funny until everything is seated. We need more summer. BUT we also need lots of water.
    Wags

  11. #9
    Senior Member IRRebel's Avatar
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    Sounds to me like simple tuning issues or maybe the carbs just need work, and/or timing. Read your spark plugs. IMO.

    If someone built the engine with a healthy solid lifter cam, I would have to assume the rest of the engine was built similarly to support it, (Forged pistons of decent compression and head work) and yeah, a rough idle and struggle at low rpm would be pretty normal. Mid rpms, or cruising, on jet boats is about 3000-4000 rpm anyway, and that shouldn't be an issue. Particularly with your 600's.

    My Moo is running a 305 degree solid cam, and 750 Holley Vac secondary carbs on a tunnel. Never a real issue save for the once in awhile idling issues that seem to pop up. She usually runs in the 3000-3500 rpm range just cruising around. Pretty good on gas as well that way. During a recent 5 or 6 mile run upriver I held it pretty steadily at 4000-4500 rpm and the thing was coming alive! Quite a few stabs at 5000 plus, and mileage went out the window doing it, but FUN!

    To each his own, but I'm sold on the tunnel ram on these boats, in a performance application. Not necessarily racing, but for solid performance boats where you want it to scream once in awhile.

    Not to say single carb lo profile style engines can't run. They can, The Moo ran initially that way, and ran hard! But you already have that setup, I would work it out as best I could before calling it dead.

    Ray

  12. #10
    southwindsforsure justsquirtin's Avatar
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    that is the same setup i am running on my southwind=850 demon=stealth hydraulic roller=alum heads=87 0ctane=75gps/mph=have been running this setup for 3 yrs no problems

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    Glendale Arizona Squirtcha?'s Avatar
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    From someone who did just what you're doing only in reverse. I was running a Weiand Stealth with a Holley 850 dp carb. I pulled it in favor of a tunnelram with a pair of 660s. Got a smoking deal on the TR package and couldn't resist. Fuel mileage went to heck and I didn't gain any performance. The setup works perfectly with no dead zones or stumbles so it's not like there's anything wrong with it. Apparently it just wasn't needed and the single carb and dual plane was enough. Sometimes I wish I'da left well enough alone.

  14. #12
    Co-Founder of SHB MarKist's Avatar
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    yeah Dan, but it looks cool as hell !!


    Markist
    "Life is SO much better now......

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    Senior Member GAWnCA's Avatar
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    I don't think Dan is the type who just wants to look cool.
    Wags

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    Senior Member hotfish's Avatar
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    Quote Originally Posted by GAWnCA View Post
    I don't think Dan is the type who just wants to look cool.
    You look up cool in the dictionary and there is a picture of Dan.

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