Hi guys, I have a 1978 Glastron jet boat with a 5.3 running EFI and truck intake. Bottom end is a $200 junk yard short block with ported and milled 5.3 heads running PSI valve springs rated for .630 lift. Current cam is a standard LS1 Camaro cam. I spent last summer just beating the snot out of this short block and it's handling it like a champ.

What I want to do is put a fairly nasty cam in it and then add a wet shot to it. So I'm looking to get a cam custom ground for nitrous. I want to stay safe within the springs limitations at around .610 lift. My exhaust is center rise manifolds where the water enters the exhaust stream after the turn down, so water reversion is not a problem with a long duration cam like on a boat with over transom headers.

If you don't how jet boats run, there is NO NEED at all for low end power. As it sits now, when I hammer the throttle the motor instantly spins to 5,700rpm for about a half a second till the pump hooks, then it drops to 5,600. I'd like to get it up to about 6,000 on motor then to 6,500 on the juice. We usually run outlaw style drags at 800 feet. If there is a safety crew they'll space the bouys out to 1,000 feet, so it will be about a 9 or 10 second long 150 - 200 shot.

BTW, when the boat had the big block Ford 460 in it, the best GPS it ever ran N/A was 58mph. Just ran 61 with the 5.3 last Saturday. On the day the pic was taken it GPS'd 63. About 99% of jet boats run big blocks, and they just hate getting outrun by 325 cubic inches.. LOL

So, any ideas on a nitrous cam around .610 that is happy happy happy at 6,500 rpm?

 

Maybe a Trex on a 5.3?? From another thread....

"Thunder Racing TRx V.2- 242/248 - .608/.612 - 110 lsa 3500-6700 RPM Power Band. Violent mid-range & high RPM power. Requires computer tuning."

Is that LSA too tight for nitrous?

 

that sounds like alot of fun

 

I know a lot of guys running nitrous on this exact cam. It responds well to nitrous. You can always order it on a different LSA. I"ve got pretty much the same cam with a 112+4 LSA for the spray.

 

That is awesome! Let me know if I can be of any help on the nitrous side!

 

Hell, the nitrous part is easy. A cam that gets the most out of the spray is the hard part. There's a machine shop around here that will grind a truck cam to any specs you want for like $60...

May try my own hand at this and grind one 234/240 - .600/.605 - 114 lsa??? Anything similar to that out there that someone has sprayed on??

 

I've always wondered, what does the +4 mean? I have to install the cam at +4. or if it's installed straight up the cam timing will be at +4??

 

Damn, made some phone calls. Norfleet Machine in Dallas, TX. $50 to cut whatever lift and duration you want into your Gen III cam. :-)

EDIT: Only to a certain point. Can't really take enough off the cam without cutting through the hardened part to make a big difference so that's probably out.

 

i found my cam for 125 bux local... its a 224 228 .581 .588 114 +2 and it runs damn good, pulls hard all the way to 6400-6500 in my 5.3 camaro and i spray it with a 200 shot all the time it responds very well. i think you'd be better off finding a used cam instead of going with a re-grind just my .02. im also running the psi max life 1511 springs

 

Yeah, that's I'm thinking. Find a used cam rather than a regrind. Will probably be just fine spraying the Camaro cam for now.

Anyway, got my solenoids, an EFI fogger nozzle and hoses from the solenoids to the fogger. What kind of hose do I need to go from the fuel rail's schrader valve the to fuel solenoid? $70 into it so far. What pills should I get for a 150, 175 and 200 shot? My used Ebay nozzle is coming with 75hp pills.

 

Found this cool little jet calculator...

http://www.robietherobot.com/NitrousJetCalculator.htm

It's showing the following with 54 PSI fuel pressure and one nozzle...

150 - .058 nitrous and .030 fuel
175 - .062 nitrous and .033 fuel
200 - .067 nitrous and .035 fuel

Sound close??

 

It really just depends on what multiplier they are using to calculate HP.

 

Ok Brandon, what hose do I need to go from the fuel rail to the fuel solenoid?

Got this cam today... 226/229 @ .050 - .575/.578 on a 114

 

hell yeah that things gonna rip, all it takes is a cam to wake these things up. im like 90% sure the fuel rail is a -4an thats were i pull fuel for my 200 shot from.

 

Would like to know for sure before I drop cash on a hose.

 

Did some searching, -4an on one end and 1/8th NPT on the other.

 

You'll need a 4AN hose and then an 1/8th NPT or 1/4NPT(not sure which fuel solenoid you're running) x 4AN fitting to go into your fuel solenoid.

 

i have a -4an male to 1/8 npt male fitting in my solenoid and a -4an female line connecting that to the fuel rail. i have the trans out of my car in my cousins shop i couldnt check the other day lol. the -4an to 1/8npt hose would work too..