Has anyone upgraded to a 4bbl carb on their Mercruiser 4.3

[Bry21317]

Re: Has anyone upgraded to a 4bbl carb on their Mercruiser 4.3

I did this same upgrade on my 94 305, 5 liter and it made quite a difference. The only problem is that I used the wrong Intake, so I have lost some low end torque. Its not bad, but I think I will switch to the Performer intake this winter, as the one that I put on it was the RPM Performer, that runs from 1500-6500 Rpms instead of from Idle to 1500 rpms.

I also used the 1409 Carb and have not yet calibrated it at all, and with my same prop, I was able to go from 48mph GPS up to my best of 53.2 gps. So I did gain quite a bit on top end, but lost some low end grunt that I did have, until the engine starts to spin good. This is why I think I am going to sell off this intake and go back to a Performer intake. So I can get some of the low end torque back. When my setup had the 2bbl it had alot of torque.

Bryan

 

[sarmstrong]

Re: Has anyone upgraded to a 4bbl carb on their Mercruiser 4.3

Im also very interested in converting to 4bbl. I have a 98 chapparral 22ft with a rebuilt 4.3 volvo and a DP...can not stand up coming out of hole but lacking in top end. To change props would be $1500 ++. I currently am dyno tested at 248hp with 2bbl but would love any response from anyone who has done the swap and how it affected top end. My previous boat was a stingray with a OE 4.3 mercruiser and 4bbl and was getting 62mph on a calm day<<<< really miss that!

 

[Don S]

Re: Has anyone upgraded to a 4bbl carb on their Mercruiser 4.3

Welcome to iboats sarmstrong, best to start your own thread with your question. Not tack on to the end of a thread with 20 some replies and expect anyone to see your question. Soon they will all be answering the original post and your's won't even be seen.