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Hi all, heres what i have and what id like to get out of my Marine 454.

Its stock internals, i have a holly 750 4bbl and dart intake, EMI exhaust, i want to get some heads and a cam to boost the hp i want to go on the cheap of course but i'll pay for the quality and durability.

It's in a 21' Ultra open bow jet, dominator pump set back with a diverter.

Thanks MikeVG
 

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Hi all, heres what i have and what id like to get out of my Marine 454.

Its stock internals, i have a holly 750 4bbl and dart intake, EMI exhaust, i want to get some heads and a cam to boost the hp i want to go on the cheap of course but i'll pay for the quality and durability.

It's in a 21' Ultra open bow jet, dominator pump set back with a diverter.

Thanks MikeVG
Hey Mike,Is that a 21LX? I know those boats very well, and as for the power plant, is it a indmar,or marine power? 454, 330 hp or 325? either way they are both good stock packages, The up grade you are looking for will help alot in that hull, I would go with a set of Merlin heads as that will go good with the manifoild you have, and a crane cam .580-.600 lift I have done a few with this set up, and they have performed very well, I am sure you would be very happy with that set up! If you have any other questions pm me or Tom from JBP,,Jet Boat performance him and his son can give you some great info as well!
Tye.:)hand
 

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Hey Mike,Is that a 21LX? I know those boats very well, and as for the power plant, is it a indmar,or marine power? 454, 330 hp or 325? either way they are both good stock packages, The up grade you are looking for will help alot in that hull, I would go with a set of Merlin heads as that will go good with the manifoild you have, and a crane cam .580-.600 lift I have done a few with this set up, and they have performed very well, I am sure you would be very happy with that set up! If you have any other questions pm me or Tom from JBP,,Jet Boat performance him and his son can give you some great info as well!
Tye.:)hand
One more question, did you buy that boat new? if so did you buy it in sylmar at west coast ultra, or did you get it in san deigo? just wondering as it looks like one that I built!
 

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Hello and welcome to PB ! Your cam choices are somewhat limited and are determined by several factors such as the valve springs, retainer to guide clearances , piston to valve clearances and piston and combustion chamber configurations, static and dynamics compression and particularly the Thru hull center rize exaust type you currently have (max duration @50* figure shouldn't exceed 237* to 240* "ish"). CompCams makes a couple good "Jet Boat" flat tappet and rollers that will work well , we also use Herbert Cams alot and One of the formost cam shaft authorities here (PB boards) is Chris Straub of Struab Technologies Good Luck Tom
 

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Hello and welcome to PB ! Your cam choices are somewhat limited and are determined by several factors such as the valve springs, retainer to guide clearances , piston to valve clearances and piston and combustion chamber configurations, static and dynamics compression and particularly the Thru hull center rize exaust type you currently have (max duration @50* figure shouldn't exceed 237* to 240* "ish". CompCams makes a couple good "Jet Boat" flat tappet and rollers that will work well , we also use Herbert Cams alot and One of the formost authorities here (PB boards) is Chris Straub of Struab Technologies Good Luck Tom
TOM I NEW YOU WOULD POP IN WITH SOME GOOD ADVISE!:)hand
 

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Discussion Starter · #6 ·
Hello and welcome to PB ! Your cam choices are somewhat limited and are determined by several factors such as the valve springs, retainer to guide clearances , piston to valve clearances and piston and combustion chamber configurations, static and dynamics compression and particularly the Thru hull center rize exaust type you currently have (max duration @50* figure shouldn't exceed 237* to 240* "ish"). CompCams makes a couple good "Jet Boat" flat tappet and rollers that will work well , we also use Herbert Cams alot and One of the formost cam shaft authorities here (PB boards) is Chris Straub of Struab Technologies Good Luck Tom
Thank You Tom, appreciate your input, much appreciated
 

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See Steelcomp about some ported large oval heads and Cstraub about a cam.
 
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