want reliable hp out of a 496
 

I'm new to boating, I know cars well but wanted to ask some performance advice. I have a 496 in a 240 baja with a b1 drive my heads are gen v rec ports with some port work comp will b around 9 to 10 open to advice victor intake 850 holley what cam should I run I'm figuring on a hyd roller around .6 .630 lift area I have a 23p mirage prop will that work or get something diff any good advice is apreciated

First question would be what exhaust are you going to run? That will pretty much dictate your cam choice. I would target no more than 9.5:1 compression to be safe on 91 octane. You would most likely be better off with an RPM airgap intake. It will have a lot more low end torque and you will not be turning enough rpm to get the benefits of the Victor intake. With decent exhaust and the right cam you should be over 500 HP.
Once everything is finallized on the build you can chose a cam. I think you'll be looking at a cam with intake duration in the 226-230 @ .050 range, with around 8 more on the exhaust ground on a 112 LSA. That would be with a decent exhaust system. This cam would probably revert water with stock exhaust. There are others on here more knowledgable than myself that may have some input as well.

Bob Lloyd
Full Throttle Marine

I have the imco power flow captain choice is there a better option for this budget build I assume my heads are gonna limit my hp

The captains choice limits the talpipe length so reversion becomes an issue. The cam has to be more conservative. Those heads will support 500 HP easily.

Bob

Do you have 454 bored to a 496...
...or do you have a 496 MAG/HO platform (2002 & later)?

Another vote for the air gap here...... I have done a ton of research and you will leave power on the table if you use a single plane intake. Over about 5,300 rpm is where you start to see gains with a single plane. Now, if you have 540+ cubic inches and are using large port heads, have a big cam with big duration numbers and a nice header setup than by all means use a single plane. You need torque from 3,000 - 5,000 and your setup needs to maximize that. I have a similar exhaust setup sing a 496 style and my cam is a 114lsa 228/233 and I had reversion with stock risers without turbulators. Taller risers and turbulators back in stopped the reversion........ Go with a known cam that will work with your exhaust.... The previous post has it right... Exhaust dictates cam selection....... I made the mistake of getting my cam first and thinking my exhaust would be OK.... I got lucky and was able to make it work. I think there has been many guys that have fried their motors because of reversion......

Since the OP said he had Gen V heads and carbureted, I assumed it to be a 454 based engine. Guess we need to know that for sure before giving advice..

Yes it is a 454 I'm learning a lot guys thank you and keep it coming should I do away with the captains choice and if so what do I need to do to accomplish

Does any one have full length risers for imco power flow bbc I f not wanna chance it