jamie 10017

To JBA there is something I always try to remember with a boat engine... Horsepower sells the boat.. TORQUE is what moves it. I tell you what I did with my engines which my not be what you want to do. 454 2 bolt block ARP studs and align-honed . Stock rods with ARP bolts resized them. Had it balanced, I have a cam grinder that worked with Mercury racing years ago to help them develop the engines so he knew exactly what I'm running, now my boat is a barge compared to you guys, 38 ft long with a 13 ft> beam and 15,000 lbs. So I went with a 060 overbore and a 210 tho. dome piston with 781 GM oval port cylinder heads. its about 9.25 cr. .Eldelbrock performer intake a HYD roller cam, Norris steel roller rockers and a marine HEI dist. I wanted **** loads of torque right off idle to about 4800 to 5000 rpms it will probable never see that many R'sI but wouldn't be afraid to spin it 6500. I was not worried about HP I wanted big torque numbers I realize the HP will come with the torque. Bottom line is decide what you want to do, have a boat that runs wfo all the time and have a hell of a time at the dock because it wont idle for crap or something you can do just about anything you want to just maybe not as fast as you could go if you had a different camshaft and cylinder heads. I admit my heads have a lot of bowl work and are port matched and SS valves but they are long way from a race head. You can get a good running boat just look around find out what you want to do and stick with your plan you have a foundation with what you have but for 1500 a engine will be tuff but I support you all the way. IT gets very expensive to change direction in the middle of a build. I was IHRA national record holder 1/4 and 1/8 mile in 85 and 86.. A/Gas ...468 bbc gm square port heads two 4500 on a tunnel ram 8.51 164 MPH would I put that engine in a boat ....HELL NO. I run a Top Alcohol Funnycar now and would I put that engine in a Boat.......Yeah just to be stupid, I have gotten older 53 and slowed down a lot but this is just my opinion that's all.

KRAUSMOTORSPORTS

iTrader: (2)

Very well worded! And I'm here for your example Jamie
My engine is original to the boat, I am second owner of my 1987' IMP Eleganze 255
Now here's my setup as follows
Original 2 bolt Main Block (stock was 330)
ARP everything.
Steel crank
Stock rods
Forged Pistons (wiseco/TRW) can't remember 10.5:1
Port match good Oval Port Heads reworked everywhere matched to Team G Intake
Solid Roller Lifter cam .693 .695 on a 104 LSA
Heads have comp cams stud girdles as well for valve train support
KrausMotorSports (me...lol) reworked 850 Holley idles great at 850-1000 and docking.
Also still running stock thunder bolt Mercruiser ignition. With 6cyl box
And huge 4.5" dry exhaust Stellings.
****now I am just freshening this setup for next season and I am looking @ around 2k for total rebuild in parts. Bearings seals, heads checked, line hone, crank cut and polished etc....
But I am only giving an example for Jamie. This is probably a MAXED setup of what the stock 330 could be? I have spun this to 6500 a few times and put me in the really low 70's. 23.5 pitch and 6500lb bucket of resin. I haven't dynoed but will this summer. My guess is maybe 500hp?? Maybe! Id love the power from my old 540ci but that's another story.

jamie 10017

I would love to have a 632 or a Sonny Leonard 1008 CID screaming under my deck but Cubic inches=Cubic Dollars , there is no Replacement for Displacement , also something I wanted to add. You will hear alot about boat engines are hard on exhaust valves, I dont feel they are any worse than a race engine , most of the time when something has happened to a exhaust valve it was because the engine was lean, making sure your fuel curve is correct is a must !! A 7.4 330 HP is not a bad place to start, especially on a budget. ....Grasshopper Boat safe and remember to pull back throttle when boat leaves water.......GO BOOM.......nuf said..

tpabayflyer

Yes, keep in mind the Vortec heads are closed chamber around 110cc vs 119cc so you get a nice bump in CR......... I pretty much did exactly what Mild says here to my 2000 L29 motor. I did do afull rebuild with forged JE pistons and scat H-beam rods. Cast crank and a set of new Vortec heads with some mild porting and 2.19/1.88 valves. I picked up a new hyd roller cam for the 454 mag motor for about $150 brand new. Lift is .510/.540 and works fine with stock valvetrain. I was after a real flat torque curve and think I got it! Max rpm is only 4,400 but I did go up a prop size from 22P > 24P Bravo 3....... Top speed in my wellcraft cruiser was 47 now 51 MPH so I gained 4Mph turning the same rpm with a bigger prop. I did use a new stock style log exhaust and would recommended a 496 dry joint if you are changing........ I don't think I gained much from using th big valves and would not recommended it. I picked p a set on eBay that wre already done so Imfigured I would give it a try. Shop flowed them and said the gains were maybe 5% and no good above .550 lift.......... One mans trash is another's gold so I grabbed them for $750 complete! Perfect for my combo!
My engine is an MPI and I had to increase my fuel,pressure a bit to get my afr's in line. The only downside for me is the engine does run rich at idle and I have to clean or change the plugs a little more often than normal.
I never run full,throttle as i Don't see the need to beat this thing to death burning 29gph as well. I can cruise at 3,000rpm at 32mph burning 12gph, 3,700rpm Is 40mph burning 20gph so that is my fast cruise speed. Engine runs great 0N 87 octane. It's not a powerhouse but makes great torque right where it's needed! building an engine is all about using the right combo of parts for YOUR needs.... TBF