Best bang for the buck!
 

I have a stock gen v. I am thinking about changing the cam to a comp 11-232-3, comp says it is the biggest for an I/O. My boat is 28', 8000 lbs, volvo duo-prop, flybridge, single bbc. Basically a big brick. Besides the cam swap + springs + roller rockers, I have 2 sets of gen iv heads in addition to the stock ones, 348772 & 348236. One has peanut ports but, bigger valves, the other bigger ports stock valves. Not sure of the # on the stock heads. I am trying to produce the most torque for the buck with the options I have. Any thoughts from your collective genius will be appreciated.

fixx
 

that cam is for a offshore/ski boat not a heavy boat you have..is your a single or 2 engine boat??also those heads you mentioned should not be used on a gen v block..do you have 454 or 502? if you want gobbs of torque your better off with stroking the engine but you may hurt the outdrive,,catch 22..

:frog::frog:

Stock 454. I have never done it but have seen many threads on using gen IV heads on gen v blocks.

I really think in that boat with a duo drive you'd be wasting your time and money trying to get an appreciable increase in speed .,Unless you want to spend some bucks .Just putting some stock oval ports heads on, an "extreme" cam in, isn't going to do much. Not trying to bum you JMO

And I should have said even with a little better choice of came ,,,not worth the effort

I did what you are asking about to a Baja 235 force. New heads with bigger valves and some mild clean up port work, mild cam and roller rockers. I gained 3-4 mph and that's on a boat that's probably more than half the weight of yours. Hate to discourage you from your project, but from personal experience I don't think you will gain much if anything on your hull type and weight.

The money would probably be better spent just making sure your present motor is everything it should be and a better sound system

The main goal is not speed. I'm working on an assumption that more torque will help me gain some efficiency. The engine won't have to work as hard to go the same speed.

Bigger cams will move the torque range up in the rpm range. Spending a few thousand dollars to save a few hundred in fuel per year is not worth it.

I can accept that, I'm not a Motörhead like many of you here. With that, back to my question about the heads. Which set would suit my needs best, the peanut ported heads with the big valves, the bigger ports with normal valves, or the stock gen v heads.

Since none of the listed heads are going to do much for you ,I would probably just use the heads that are in the best condition, meaning need the least amount of money to bring up to par.JMWAO

just find some large oval ports cheap that came off a car or use the ones you have if they are not too rotted out - have them gone through all new valves etc, probably cost you about 1000-1200 for a fresh set of oval ports all machine work done with inconel exhaust valves severe duty intake

also about the gen iv heads on gen v there is a special headgasket for this, honestly i would find a good machinist and talk to him about it

This thread started with a guy with a running bb that he was thinking he could do something with by changing to a different set of heads and cam. All this on a heavy non performance type boat with a Volvo duo-prop. Most responses were that it would not be money well spent .Now you are saying he should rebuild some passenger car oval ports with all new valves ,,,and then what .Why spend the dollars .To the OP If your stuff is still together ..run it ..If it's apart, check and rebuild the best set of heads you already own ....and go boating. Spend your dollars elsewhere .My opinion

^^^^^^^^^^ Good advice

my
 

X girlfriend ???:lolhit:

My 26 ft well craft cruiser 7.4 MPI needed a rebuild so I installed larger valves and did some minor port cleanup.....these were vortex oval port iron heads. Also I used the HO cam .510/.540 lift and it performs very well......top end up to 51 from 47 using a 24P bravo 3 and cruise speed is a bit higher. MPI Needs tuning if you increase power an I was able to do it using an adjustable fuel pressure regulator and Wide band LM-1....... Mods Did not cost me much as I was rebuilding the engine anyway. I would say if you are rebuilding the engine to go with a str0ker 496 and get a decent exhaust. Don't expect too much improvement in overall performance.... I figure my motor makes about 75 more HP than stock but the difference is not really noticeable in everyday cruising.... TBF