Scottski

First, thank you to everyone who has answered thus far. This has been my first post on here and the wealth of knowledge from all of you is greatly appreciated.


Actually I snuck it in at the very end of the OP. It has Glenwood Aluminum Manifolds and Stainless risers. Now, the set up is plumbed different than what I'm familiar with coming from inboard PCM powered ski boats. the manifold itself was plumbed with an in and out, as was the riser. Then there are block off plates between the two. So water cannot go from manifold to riser, they are separate And part 2, it is a 2 bolt main, however 3 marine engine builders have told me as long as I didnt make a beast of the engine that Id be okay on the 2 bolt. They all were told Id be 500 + or - HP. So I hope thats true because I got a call about 20 minutes ago my block has been bored cleaned up and ready....

I understand the flywheels not bolting from 4 to 6, but will the dampner bolt to the Gen 6 flywheel?.

You are correct, merctrans w/ the extra clutch disc mod and was told parts were... I cant recall the word terminology, but made stronger or hardened in some sense, foriegn language to me. Cryo something??

that was my thoughts exactly on the 454 which is why I hadn't pulled the trigger on it yet. I was thinking that in order for it to be what I wanted, Id be as much into it or more than doing my block or starting over completely.
And thank you for the clarification on the lifters. That makes sense

In all honesty I was pretty happy with the boat before with speed. And from other readings and finds from here on OSO, based on what was done to it, I think it should have had a cpl mph more. Maybe it was wrong prop, carb settings, combinations of several things. I'm not looking to make it an 80+ boat, I know there would be a ton more to do other than engine, but if I can knock on 70 Id be thrilled. And as mentioned, a solid 45-50 mph cruiser, without stressing it, is my main goal. 95% of it life will be on smaller lakes here in central FL and running up the Caloosahatchee. And even when out in intercoastal or ocean type running, Im not one to beat myself or my boats up so I don't plan to be hammering it through 4 footers, ever... that'll be the next step up boat, whatever that may be, HA!

Again thank you all for all the info so far. Such great knowledge here.

Scottski

Bill K, please clear out your PM inbox so I can respond. Thanks

Scottski

I'm goin to investigate soon where exactly my exhaust and water mix in my risers. i was just outside looking at it and cant visually figure it out.
I may have to call the previous owner that fabricated them to find out

Scottski

I finally got to examine the risers today. Looks like the water is mixing basically at teh end of the tail at the transom. The risers are stainless, 6" rise and then they angle downward to exit the transom at about the level of the exhaust manifold.

I'm changing plans a bit and not going the 496 route. Ill keep the standard stroke, block was bored 60 over. Will be align honed. Scat crank, forged rods and Wiseco Forged pistons 10cc dome, .Hastings rings and King Si series bearings.
Comp Cam K-11-451-8 Kit Hyd Roller - (confirmed this is a retro kit and will work in my Mark IV according to Comp Cams help line. Need to get wear plate and button), WP Merlin 030040M-2 Iron Oval port heads 119cc.

I found a HP estimator and after figuring out all the numbers it needed, it looks like Id be in the 430hp range. My old set up, according to that same calc would have been about 405hp, both at about 4300rpm. Don't know how accurate that is but it was kinda fun figuring it out.

GPM

My opinion, you would be much happier with the 496 at basically the same cost.

Scottski

Even w/ a 2 bolt? Most seem to think thats a bad idea. If I do that, My option would be forged crank and keep my current flatt tappet cam. Im about 1500 over what I can realistically afford and cant do it all the way Id like to, so Im trying to get the best bang for buck

GPM

You can have the machine shop add the 4 bolt caps if that's a worry. You don't seem to be going for max power, the 496 would be stronger across the RPM range and you wouldn't have to crank it up as far to get the top speed. My opinion, more cubes in a boat is always better, a mild 496 will do the job easier and better than a 468.

Scottski

Thank you GPM, I read about the added bolts upgrade. Ill talk to my machinist about it and explore that route. And no, I'm not going for max power. Someday in a newer lighter boat, but not this one.