Hello,

This year I picked up my first boat. A garetta 24 with 454 carb with thunderbolt v and bravo 1 drive. At the moment it doesn't really run that well. Have been diagnosing an issue where it doesn't rev out all summer (it stops at 3500 rpm and starts missing, sounds like a rev limiter). Runs about 50 mph at 3500. Have noticed that it also uses a lot of oil, about a quart every hour.

The seller I bought it from swapped engine because when he was about to sell it to me he test started it and noticed it pushed water through the crank ventilation. Have been talking with a machine shop owner that thinks the oil issue could happen if the previous owner only swapped blocks and used the same internals from the previous engine.

The oil issue is the main reason I'm planning on rebuilding the engine and since it's already out of the boat I might as well upgrade the parts I'm replacing anyways. Also might swap out the complete ignition system for an aftermarket one (been thinking daytona sensors since the machine shop sells those). Thinking this will be a nice winter project.

Now to the questions I have. My budget is about 10k and I (obviously) want to make as much power as possible to pick up some mphs. Goal is 70mph but more is better of course. What road do you guys recommend? Most of the labor will be free except for the bore and hone. From the research I've done it seems like a 489 stroker build might fit my budget best. Looking for recommendations for parts as well.

Is running stock rods possible with this build or is it best to swap all internals?
Is porting the stock heads for this application possible? Or completely out of the question and new heads are needed? In that case which ones?
Carb and cam recommendations?
From what I've read it seems like exhaust upgrade is always needed. What exhaust does people run?

Or is it better to go the forced induction route? Anyone tried turbos?

Pretty new to engine building but I like researching and are surrounded with people that has a lot of experience. But not with boats. Only engines in other applications. Therefore I'm asking here! Replies to any or all questions is greatly appreciated!

Tried attaching some pictures of the boat (because everyone likes pictures) and engine cover but couldn't yet because of the post limit. But the engine serial 0F810432 and it says it's and MCM 7.4 bravo if that is to any help. Not sure if it's still correct after the swap but I think so.

Thanks in advance!

I’m looking to discuss and learn!

The SWAP renders all serial numbers irrelevant.
with that said, your engine block has a serial number (rear deck surface) and the heads have casting numbers (under the valve covers).
in order to START giving advice we need to know at LEAST those numbers.

The original MCM454 had an iron 2 plane spreadbore intake (not good for performance), low compression cast pistons and cast crankshaft (neither the hot ticket for hp), and peanut port heads (also not great for performance).
If you get your block ID then we can tell you whether you have provisions for factory style roller cam. The head ID numbers will help us advise you depending on your hp goals.

X 2 :thumbs
Whatcha’ got Willis ?

How about if his motor is the 454 365 mag, aren't those supposed to be aluminum intakes. Are the mags much better for upgrades?

If its labeled as a 7.4 then its most likely the lower hp 310/330 with a 2 bolt main block and peanut port heads.

Here are some old threads on building 330's
My 330 on Roids - Final Results - Offshoreonly.com

330 on steroids? - Offshoreonly.com

454-330 build up help - Offshoreonly.com

Aha! I'm not able to look at those right away. Let's say that's the case. Is it better to just find another block then? Too bad they are a bit harder to source over here in scandinavia.

I'll post the numbers in a day or two

Thanks for the tips Griff!! Will make sure to read those!

Look for "Crazyhorse" (Dave) and "Dyno" (Don) in those 454/330's on steroids threads....Crazyhorse is very smart and he worked as a machinist in a speed shop for several years and builds his own stuff. He's a friend of mine and lives close by and I see him and talk to him periodically. I haven't seen Dyno/Don for several years.

Dave and I were just talking about "SuperV's 454cid engines that he built back around 2006 pr so...cast cranks, 2-bolt mains, 3/8" rods reconditioned and ARP rod bolts, hypereutectic pistons, flat tappet hydraulic cam, made 505hp @5500-5600rpm on Tom Earhart's dyno back then.

SuperV put about 400-500 hours on those engines and just sold the boat---they're still running fine over all these years. I will call Crazyhorse/Dave and talk to him more about it just to make sure what I am saying is accurate info from those engines he built

Did that dyno don have a red boat with a radar arch?