Need some help on engine mods.
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Need some help on engine mods.

  1. #1
    Member steveo-85's Avatar
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    Default Need some help on engine mods.

    Hey guys, I have a 18 bahner with a pretty much stock 454, oval heads, stock bottom end, berk 12jc pump, as far as i know the pump is stock, What impeller would that be? The boat will run about 65 tops at about 4500 rpm's . Im planning on a single carb tunnel ram, Mainly cause i like the look, I was thinking about a cam and maybe some solid lifters to gain a few more mph and rpm's ? Would that be a mistake or would it help with the pump i have, or what kinda ideas do you guys have for just a little more speed on a budget. It has threw hull exhaust with snails. Do i still haft to worry about what cam i get?

    thanks guys
    Last edited by steveo-85; 01-03-2011 at 08:59 PM.

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    Quote Originally Posted by steveo-85 View Post
    Hey guys, I have a 18 bahner with a pretty much stock 454, oval heads, stock bottom end, berk 12jc pump, as far as i know the pump is stock, What impeller would that be? The boat will run about 65 tops at about 4500 rpm's . Im planning on a single carb tunnel ram, Mainly cause i like the look, I was thinking about a cam and maybe some solid lifters to gain a few more mph and rpm's ? Would that be a mistake or would it help with the pump i have, or what kinda ideas do you guys have for just a little more speed on a budget. It has thru transom exhaust with snails. Do i still have to worry about what cam i get?

    thanks guys
    your gonna get many many answers to your ???...my suggestions are: "stay away" from the 1x4 TR...there are alot better 1x4 manifolds out there (Dart, Brodex, Team G, Edelbrock RPM Air Gap etc in both single plane & dual plane)...carb choice would be a Holley 750cfm or 800cfm DP mech sec...cam choice would be a complete "roller" set-up, either solid or hyd lifters...cstraub here on the boards can help you out with that...he makes cams & will not steer you wrong ...depending on what heads you have (open/closed), you could do some port work & bigger valves (make it breathe better)...maybe later down the road, a place diverter, shoe, ride plate would be in order ...these mods are just what i would do if it were mine & are not intended to influence you in any way, just sayin' my .02 cents

    stay tuned...alot more answers on the way!!!

    FastRat

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    Member steveo-85's Avatar
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    I kind though that would be the answer. Im ust the pavement drags, this maching the engine and pump are new to me, I dont want to take a step the wrong way, I had a 750 dp on it for a weekend and worked on the damn thing all weekend trying everyting to male it work, just choked it out, to much fuel, I stuck a 650 vac sec on it and it ran great out of the box, I like the polished air gaps,

    What about a cam and lifter set and air gap and try the 750 dp again?

    thanks

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    Senior Member coonass's Avatar
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    just tore down my 496 this winter and looking to part it out

    I have a nice oval port T/R with 2 holley 750 dp's, scoop, reg,lines and linkage

    I also have a set of Alum heads and solid cam set-up with girdles. pm me if interested

    I'll sale the whole top end to you as a package

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    You said a couple of important things. Stock bottom end and stock pump. It would make sense to decide exactly what you are trying to accomplish with the mods. Are you going to be a racer or just a cruiser? Changing intakes, carbs, and or cams typically result in making peak torque occurr at higher rpms. That means more stress on the rotating assembly. End result can be cool parts on the top side of the engine with rod and or crank blown out the bottom. There are guys who can give you an idea of what Hp and Rpm you can reliably get out of a stock rotating assembly. My guess would be about 450 Hp at 5,500 Rpm. Again there are members who will have better insight than I. In the end, 65Mph is pretty respectable. Going to cost another 75 to 100Hp to go 70Mph.

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    where do you live & where do you boat at?

    FastRat

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    Member steveo-85's Avatar
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    I live in oklahoma, I boat in 3 local lakes.

    From having lots of street and drag exper i think my engine is in the 300 to 350 HP range, I just figures the engine could handle another 500 to 700 RPM's and maybe another 5 MPH?

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    Senior Member CK7684's Avatar
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    I'm going to say exhaust also. 65 mph is pretty good...to get much more power it is going to need to breathe...
    I'm guessing you have an "A" impeller...?

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    The Good mrjoshua's Avatar
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    When i rebuilt my 12jc it had not been overhauled and from the factory was an "a" and spun 4300 rpm with an old olds 455.

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    Senior Member MR.Magoo's Avatar
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    hey steveo did ya find the parts you are needing?

  13. #11
    "BEER BUDGET RACING" Bodean's Hammer's Avatar
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    Quote Originally Posted by steveo-85 View Post
    I kind though that would be the answer. Im ust the pavement drags, this maching the engine and pump are new to me, I dont want to take a step the wrong way, I had a 750 dp on it for a weekend and worked on the damn thing all weekend trying everyting to male it work, just choked it out, to much fuel, I stuck a 650 vac sec on it and it ran great out of the box, I like the polished air gaps,

    What about a cam and lifter set and air gap and try the 750 dp again?

    thanks
    Just think of matching the engine to a ring and pinion with the cam selection. Where do you want to make all your power?

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    how much rpm can you expect to get out of a fairly stock 454 with logs/snails by switching to a say jacketed header? i dont want to go full headers, but i know the logs are a giant bottleneck.

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