Re: Worthwhile upgrade or complete waste of money?
edelbrock 4bbl carb and performer intake would certainly make a difference. Maybe another 2-3 mph. Of course its your decision whether the extra fuel bill is worth it.
It's not going to make a very significant difference.
The only way to make significant (noticeable) HP in most marine engines by adding additional fuel flow (capability--using a bigger carburetor) will be to improve the heads (airflow), increasing displacement or increasing the RPM etc so it can take
advantage of the larger carburetor..
RPM is sort of limited because the drives don't want to turn more than about 5000 RPM.( yes I know people routinely turn drives MUCH faster)
If you want more power, plan to build up a stroker SBC aluminum engine with aluminum heads, manifolds/risers. You'll have (A LOT) less weight and a LOT more HP. (be careful with your "throttle hand" or you'll break that Alpha!)........Oh......BRING LOTS OF $$$
Operating the boat at approx the same speed (loaded with the same weight) will yield approx the same fuel flow regardless of engine. (
BFSC of most marine V-8s is approx the "same")
The above link implies why a 454 might "use" more fuel than a 383 or 350 etc in the same boat. It's not that it has a worse BFSC as the smaller engines, in FACT, it's approx the same! it's that the engine (installation) simply weighs more and takes more (produced) HP to drag that extra weight around at the same speed.
So in a nutshell......... Just changing the carb for a bigger one (2 bbl or 4 bbl) doesn't do enough to justify the cost.
