Originally Posted by KAAMA

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

Originally Posted by jocke

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!

Originally Posted by jocke

But do you ever rev a boat engine that high?

Originally Posted by SB

Yup, if that’s where it makes it’s most power.

Why would you build a motor that makes most power at a certain rpm and never run it there….ever ?

Originally Posted by jocke

I've read through those and that's about the same horsepower I'm hoping to make. But do you ever rev a boat engine that high?

Originally Posted by SB

Yup, if that’s where it makes it’s most power.

Why would you build a motor that makes most power at a certain rpm and never run it there….ever ?

Originally Posted by jocke

I understand that but just assumed that you usually build boat engines to make most power at lower rpms. Don't know where I got that assumption from though

Originally Posted by Brad Christy

Jocke,

From what I can gather from reading the many threads on the topic, the key difference between a street engine and a marine engine is in the clearances in the main and rod bearings. There are always differences in how we establish torque and power curves, but that is the same as with street engines in that we build to and “gear” them to a specific purpose. But the fact that a marine engine will spend extended periods of time at WOT, or even at something short of it, mandates that we build more clearance for all those parts to spin their guts out that whole time. We also (typically) use considerably heavier oil and make more effort to keep that oil cool.

Thanks. Brad.