Mercruiser 350 HP Question

[R8derfan47]

I have a 1992 5.7l (350)235 hp bone stock mercuirser Alpha1 with the ThunderboltIV ignition. I would like to know what is the best way to get more horsepower. I'm looking to gain 30 or so horse if its not to complicated or expensive. What is the difference between the 235hp motor and say a 260 or even a 275hp motor? Is it as simply as a cam, carb and exhaust or is it more then that. Any help would be appreciated.

 

[fone_man]

Re: Mercruiser 350 HP Question

You would be looking at bolt ons such as Carb, EFI, etc....<br /><br />EX: 5.0 litre (305 CID) w/2 bbl was 200 HP in 81 & 5.0 litre (305 CID) w/4 bbl was 228 HP<br /><br />I am using this above as example because I had one & the assumption with your 92 model 5.7 litre would be the same... but to give you a more postive answer would require research which I do not have time to do right now but when I do, I will repost...<br /><br />

 

[R8derfan47]

Re: Mercruiser 350 HP Question

Thanks for the input. I already have a 4 barrel on the boat but it is a small one. Holly spread bore I think, it's the stock carb. This engine has never so much as had a valve cover off of it.I will look at it tonight and try and get numbers off of the carb. Any way of finding out what the spec on cam is? Thanks again for your time

 

[R8derfan47]

Re: Mercruiser 350 HP Question

Checked it out last night and the carb is a Rodchester Quadra-Jet s/n 17080561 if this helps. I have no idea of it's cfm.