Engine Chang out

[LuckyPenny]

I have a chance to pick up a 27 foot cabin curiser that currently has a Volvo 7.4L (454) installed. The original engine was a 305 and the current owner changed them out. The engine so overpowers the boat that it gets upwards of 45MPH and is the noisest thing on the river. If I do purchase it the first thing I need to do is replace the 454 witha 350 (max).<br />Question: Would a dealer swap the 454 for a 350 and apply some of the difference to labor? If not what is a 7.4 Fuel Inj with less than 100 hours worth? How much could I expect to pay for a 350 Fuel Inj. (rebuilt)

 

[airman]

Re: Engine Chang out

Would it not be cheaper to simply change the exhaust? Depending on the installation access, an engine change can vary from 12-100 hours. I would simply throttle back and enjoy knowing the power is there if you need it. It is often cheaper to run a large engine at 1/2 than a smaller one at 3/4 throttle. It certainly won't burn much more fuel and it will likely last much longer. I don't think it's that overpowered at all.

 

[LuckyPenny]

Re: Engine Chang out

OK, how would you recommend quieting the exhaust?

 

[BRIAN03]

Re: Engine Chang out

I would find another boat to buy. I always say you buy the power first and then look at the boat. Not buy the boat and except the power.

 

[SS MAYFLOAT]

Re: Engine Chang out

Luckypenny, I have a 27' also. Big and heavy and has a 350 in it. I'm wanting to repower to a 454 due to being underpowered. 2 people, fully loaded with supplies and gear, she barely is able to get up on plane. I have trim tabs and all the stuff to get it up, but it is just underpowered. I would keep what it has. There has to be a reason why the previous owner went to that extreme to repower the boat. I would think fuel efficiency would be better with the 454 than an underpowered smaller engine. I know my 350/carbed engine can keep up with a small shop vac when it comes to sucking up gas! <br /><br />They do make inline mufflers for boat exhaust, iboats should have them available. I haven't checked, but I would check with them first.<br /><br />BTW, I agree with Brian03, If the boat has something that bothers you, don't buy it. It will always be something that is going to pick at you until you feel comfortable about it. Your purchase should be an enjoyable experience that fullfills all your expectations.<br /><br />Good Luck....SS

 

[tylerin]

Re: Engine Chang out

Luckpenny,Personally, I'd stick w/ the big block, for one reason its already there. Need to know what exhaust you have on it right now in order to figure out how to quiet them

 

[LuckyPenny]

Re: Engine Chang out

The current exhaust system is a cross-over to a single pipe. All nice heavy black rubber hose. Actually, I am not dis-satisfied with anything other than the noise. It hase the perfect layout for my needs.

 

[Walt T]

Re: Engine Chang out

Is it thru hull exhaust? If so go back to stock through the drive. If it is already through the drive install the standard metal Y pipe from Volvo, that will quiet it right down. DO NOT go to a 350. It will still be noisy with that exhaust and will be underpowered. Listen to us. We all will say the same thing. Lots of experience here on this board. You are the only one I have ever seen ask about actually dropping power from a boat.

 

[LuckyPenny]

Re: Engine Chang out

Thanks for the info. The boat does not have an outdrive, it is a straight shaft. The exhaust run is pretty long. As for the piping. it is rubber all the way from the manafold out the transum. To be honest, I don't remember seeing much of a muffler either.

 

[Walt T]

Re: Engine Chang out

Running metal pipes will quiet it some, but not much. Changing to a 350 will not quiet it. If you dont like the noise, don't buy this boat. It's not what you want. Even with metal pipes and mufflers it will still be very loud. You can get a nice 27 footer with a 454 and any manner of sterndrive that will be nice and quiet. Twin V-6's will work well in that size also.

 

[DJ]

Re: Engine Chang out

Luckypenny,<br /><br />I think you answered your own question. I take it this a direct drive inboard or V-drive?<br /><br />If so, installing a muffler is not a huge task. There are many configurations available both in line and wet sump.<br /><br />I agree with the others, keep the power, work on the noise. Any angine with the same exhaust will result in the same dilema-noise and less power.

 

[rodbolt]

Re: Engine Chang out

yep gotta agree with the rest. wear earmuffs if nessasary but keep the big block. use 1/2 throttle and go for years.<br /> good luck and keep posting

 

[Buttanic]

Re: Engine Chang out

Luckpenny.<br />I would check to see if you have enough space to install a Vernatone muffler . Dual exhaust with two mufflers would be even better.<br />Buttanic <br /><br /> http://www.centekindustries.com/prod_02.html

 

[scamper]

Re: Engine Chang out

I have two 454’s and there quite. At 3300 RPM you don’t need to scream. I don’t think a 27 footer is over powered with a 454. Less than $200 for an uplift muffler. I’ve got one on each engine.

 

[jam39vw995]

Re: Engine Chang out

Luckypenny,<br /><br />yup, listen to these guys, they know what they are talking about.<br /><br />Do a search here for underpowered, repower, more power etc. and the same thing rings true.<br /><br />There is not much you can do with an under powered boat.<br /><br />Work on quieting the noise down.<br /><br />A 27' boat that'll do 45 is way cool! Not over powered at all.<br /><br />I haven't bought yet, I'm still trying to find the boat for me.<br />I want power to spare so I don't have to run the motor as hard, but this is getting quite hard for the size of boat I want 18-19' but I want a 350 in it, 305 minimum.