Carb size/model in 91 barefoot

I just need to know what size carb came stock on that 454.
Thanks!

RA052007 list price $1049.95! Ouch!!! I have one on my 502 800cfm Marine!

Why not run a standard Holley? I use an 800 CFM 4150 double pumper on my 454. Probably would have been better with a 750, but the 800 was cheaper at the time and don't know what engine work I may do eventually. Well under $1000 even after adding electric choke and fuel lines.

http://www.summitracing.com/search/product-line/holley-model-4150-marine-carburetors

Of course, which is why I provided the link to Holley marine 4150 carbs on Summit. Choices are 600 CFM and 750 CFM. I would run a 750 CFM if no plans to spin the engine at a higher RPM. 600 (and evne 650) would be a bit small for a 454 and lack top end power, but likely wouldn't be a big deal unless you're sustaining max RPM. Unless you're running flat out your fuel consumption will be comparable between a 650 and 750. A 750 is not so big as to result in a significant loss of throttle response on a 454 when compared to a 650.

I would not recommend a 4160 as the boat was originally equipped with. I do not care for the lack of a secondary metering block or lack of externally adjustable floats on most.

What is wrong with your factory carb that you don't believe it can be rebuilt? Typically it will be worn out bores in the base plate. You can buy a new base plate for around $100 and a rebuild kit for $50 if that is the issue. Personally I never put any money into 4160s as I feel it would be better spent on upgrading to a 4150, but that is an option to repair your existing carb and get it going for a bit less money than a new carb. The rest of the carb should be serviceable as there's really nothing else to wear out that isn't replaced with a typical rebuild kit.

Put a 600 on my 86 bfn 454 stock, worked great, 48-49 mph

TRBenj wrote: I am curious if the above info is based on practical experience with marine 454's, or if its automotive (or paper) based. I do not believe PCM (or any of the other marinizers) would have spec'd a carb that significantly limited an engine's performance in stock form. The 650 works just fine on 330hp 454's. Since they generally only spin to 4400 or so, carb calculators indicate that a 600cfm might be just fine, though Im hesitant to suggest that not having gone that route before. I do know that 750cfm is well beyond what a stock 454 would require.

This is based on paper research, engine dyno programs, automotive experience both in cars and truck/towing applications, as well as experience with my own marine 454.

A 650 is marginal for any big block, but typically sufficient for a mild low RPM engine. My 454 spins to 4800-4900 RPM with the 800 CFM Holley on it, with a 600 CFM Holley it turns less, though I forget exactly how much. I did not spend significant time tuning the 600, I simply ballparked it based on my experience and it ran fine but lacked the top end as well as acceleration with the 800 on it. I did not measure fuel consumption with the 600 but it should be comparable to the 800 if both are jetted properly

I have also under carbed a 460 built for a broad flat torque curve for towing and it was a huge difference in power and throttle response at all RPM going from a 600 CFM 4160 to a 750 CFM 4150. Predominantly highway fuel consumption on the tow pig stayed about the same when making this change.

Interestingly enough my tow pig's 460 gets about the same fuel consumption towing at 65-70 MPH as my boat's 454 does lightly weighted at 22-23 MPH, 6-7 GPH.

Regardless, a 4150 is superior to a 4160 as it can be more easily tuned properly for the engine and boat without messing with metering plates and such.