To do or not to do?
 

I am thinking of a few upgrades for this winter, what do you think? The boat is 88 311 420s 25p 3 blades. I will run a consistant 68-69mph and a best of 70.8mph (gps). I am looking into putting a set of headers, water pump crossover, and intake not sure which one. Im sure after that i will need a different set of props. What do you guys think? Does anyone have and experience with something similar to this.

I am literally in the same boat as you are. I ditched my silent thunder and upgraded to imco exhaust but i'm still right at 70 gps. Which 3 blades are you running? I'm using the mirage non plusses in 25 pitch. I am curious to see what gains you see out of your upgrades. :drink:

Im pretty sure they are quicksilver. The 70.8 was a wild ride with just me and my wife in the boat. What type of exhaust did you put on? I took a 5 in hole saw and drilled holes in the bottom of my swim plat form to make it a little louder. I hope that there is someone that has done a few of these upgrades to there boat so i have some real world results. It is going to be hard to spend $3000-$4000 on exhaust and hope that it helps.

What RPM's are you both turning? And I assume 1.50 drives? It all depends on what RPM's your motors can take because you need more r's to get more speed and then torque will come into play to turn a bigger prop. I cant imagine just an exhaust change doing much. I am running 502 ci 465 hp bravo's at 5100 RPMS 1.36 drives with 24p agressively labbed bravo 1's from BBLADES and I see on a good day running light 74MPH my setup also has GIL exhaust.

I would like to try 2" shorter drive depth to get let wetted friction but that is alot of $$. Also my boat runs just as good with stock 23p Mirage plus props.

i am not %100 sure but i would assume that they are 1.5. I have one motor that that turns 5100 rpm and the other turns a little over 4900. I have noticed that while running down the lake that my rpms are not sink with each other. Dont know if that would have anything to do with why one motor turns more rpm. I would like to get away with not having to put an exhaust on, I would rather do intake cam but I was told that the exhaust was a must.

How long have they turning different rpm's? How many hours? I would say the top ends might need to be gone through and you could change cam, intake and carb then and that is correct depending on what exhaust you have you would need a drier exhaust to prevent reversion.

I have had the boat boat for 2 summers and put about 60 hrs on them and they have a total of 550 hrs and they have been doing that since i have owned it. I dont beat the **** out of it but i do open it up if im lucky once when i go out. I think that the exhaust is stock and if it would do then i would rather not change it, i would rather do the intake cam roller rockers but i don't want that to be a waste of money if the exhaust is going to restrict it either.

The problem is the exhaust is restricted butthe real problem is it runs wetter with water inside of it and closer to the engine so what will help you get more power is a cam but if you go bigger on your cam you could get water (reversion) into your motor. Buy exhaust first CMI etops are $2000 per set then you will have the exhaust for when you rebuild the motors to go bigger on cam.

So leave it alone keep it a turn key boat and enjoy it.

The $$ will add up quick to go much faster! I am going through both my motors due to a valve failure late Sept and I am looking at $13000 to have both re-done with new heads, cam and intake.

The 420's had decent exhaust from the factory if they were gil's. Mine were the wet joint hydrolocking version so I upgraded to imco's for reliability and weight savings....no performance gains there over stock. Additionally you should already have the crane gold wide body rockers if you have the 420's, just open the oil fill cap and check, it will be obvious.

That is correct but for him to upgrade to the Roller cam is about $1000 per enging for the roller cam/springs/ligters. What model Gils would it have?

It should have had either the crappy two piece manifold and 90 degree riser with stainless tails or the 4" gils from the factory...merc switched to the gil's due to water ingestion problems from the earlier style. They are listed on bam's website.

with the cash boats are bringing i d leave it alone enjoy enjoy enjoy use the cash to buy more gas

Unless you are ready to spend good money then I would also leave it. My motors read off the same as yours for RPM. I am spinning 23's however. I am going to try out some 25's and see how it goes.

I was looking for a few more mph and not spend a ton like everyone else, didn't really want to do a set of headers and if the ones i have are fine then i will continue to run them. The guys that i run with all have singles and are a little faster, so like everyone else you want to keep up or be a little faster. I guess i will wait till they step it up and get a real boat with a pair of motors.
Audiofn Unless you are ready to spend good money then I would also leave it. My motors read off the same as yours for RPM. I am spinning 23's however. I am going to try out some 25's and see how it goes. You are running 23p 3 or 4 blades.

just a thought but you could also step it up and get a boat with a beak

The 420's in 88 came with TRS's, which are run pretty deep, also 1.5 ratio. You will get your best top end with a 3 blade most likely. I dont know about the reliability of the early Gil manifolds that came on the 420's, but your not going to pick up any performance by replacing them.

I ran 550hp 502's in my 311 with TRS drives and it ran in the upper 70's on GPS. I dont think a cam change and intake is going to give you a noticable increase.

At 550hrs, I would say your getting close to a valve job and new valve springs to help keep it reliable. As mentioned, its easy to spend a ton of money on a boat, ,make your investments wisely.

LE

Thats a good idea, cause you don't see very many fountains on the water. I don't know why would anyone want a boat that you can put 5 people and a cooler in the cockpit.

correction i can fit 6 in seats and a cooler in the cockpit and walk completely around my motor. Im not a rocket scientist but sounds to me like this whole thread was about speed, horsepower and keeping up with the guys you run with.

This whole thread WAS about speed, horsepower and keeping up with the guys you run with, not about what kind of boat do u think i should buy. Forgot u have one of those big 24ft i mean 29ft fountains, that can seat 6 and have cooler in the cockpit. Thats where Formula went wrong when they didnt make it so you could walk around the motors, cause thats where most people spend alot of time. Thanks for your thoughts.

You forgot the part about those guys needing to step up to twins so they can spend more money in fuel and you can keep up

http://www.facebook.com/photo.php?pi...16&id=39501741


Saved alot of gas that day. You done hi jacking yet.

The really cool thing is if you get a 24' oh I mean 29' Fountain you can idle everywhere you go at LOTO because they can run in the rough.

I would love to come down for the shoot out. Think someone told me that it was about 8-9 hrs. Heard the water was nasty and the water partol was pretty bad, but from all the videos ive seen, it looks like something id like to try atleast once.

Its a party while watching a few boats race down the course. What do you mean by the water is nasty? Rough or dirty?

Dirty heard it was a nasty like sewage, and the same person said that the water patrol was bad.

I depends on the rainfall and if the upper dam is open. It is not the cleanest but when you see the boat traffic and homes on every inch of shorefront you can see why. In the ofseason you can see the bottom in about 5ft of water or more but in the summer maybe a foot. You cant beat the bars and activity that you can do by boat. If I were to come down for a good time I would pick a holiday weekend and just go to party cove!