manalski

Hi guys,

Im new on here.

Im building a 4.3mtr alloy jet boat and iv got a stock ls1 for it, i havnt ran it but it seems and looks stock, and iv been looking for some parts to buy for a bit of added hp.

Iv seen theres two fast mainfolds and throttle bodys, the 92mm and the
102mm is the best option the 102mm setup? along with the fast fuelrails and iv also taken a shining to the RHS heads..

RHS 205cc Aluminum Cylinder Heads 580" Max Lift), 205cc Intake Runners, 62cc Combustion Chambers. The heads are bare castings that have been fully machined for 2.020 /1.600 valves, would these be sutible on a stock motor or would i have to change the pistons and injectors aswel?

I know il be changing the cam as il need constait constant torque up to 5500rpm. im also planing on buying some lightening marine headers and they have 2inch primarys.

This is whats got me going but is it suited?

http://www.ebay.com/itm/FAST-LSX-GM-...90777241210%26

Im based in New Zealand so im only limited to internet shopping but il be traveling to canada next month and hopefully cross the boarder to see whats going on.

Thanks for your time,

Mike

jetboat

I was going that way but our low RPM it does not make sense to do after market heads and intake they are for high RPM. go to truck heads and intake maybe mill the heads for more compression get cam spec by patrick G you want torque. what jet and impeller are you running. But what do I know not much

manalski

Im running a scott 8 1/4 inch sprint unit so it can take rev's up to 6500rpm 7rpm..not that id be doing that, id be happy with 5500, i cant remember the impeller specs but it came out of a sprint boat running 500-550hp

jetboat

Look hard At at dino sheet hear the truck parts are cheap you mite the heads flow good and the long tube intake make good torque then do a cam you mite be surprised a HP and torque those heads and intake you are looking at start working above 5500 that a lot of money you could do forge rotating ***. with compression of you chose

garygnu

are you working with a 4.8 ls motor ? what head casting numbers are on the motor you plan on installing ?consider some stock GM 243/799 heads.a truck intake makes good power up to 5500 rpm.look at comp cam 54-455-11 for good low end torque.stock injectors should work with a mild build up .what ECM and harness are you using ?

manalski

il keep an eye on ebay for some then

manalski

Hi, Its a 5.7ltr with 241 heads, the comps a stock delphi one and the harness is a custom made one for the boat. the guy who made the harness tells me hes pre tunes the comp to 380hp..im not sure how true this is.

cheers for that, il keep a eye out on ebay for them. iv brought a ls2 intake manifold but after reading up more on it it seems like a waste of money.

94Z28-MSTGKLR

iTrader: (20)

Yeah the ls2 intake is practically a paper weight. You would have been better off with an ls6 intake if that is what you were looking at. A truck intake is going to be what your looking for being that you need a pretty solid amount of toque on tap along with a smooth curve. A custom cam is going to be a must for you're application. There is no off shelf cam that will benefit you in a boat. I know FAST makes an intake that is a truck version. It might be worth looking into. I've never heard of anyone ever tuning a car to an exact horse power number. That sounds like some one who doesn't know what their talking about. 241 heads may work out just fine for you if you get them milled to bump the compression to mate with whatever can you have cut. Sorry I'm not much help.