Jeysson,

Would you be happy with around 450-460hp? If so why not closely follow the "330 on roids" build? Granted you have mag motors, but he used 496 exhaust and a custom grind cam(you could still use flat tappet) and get some decent pistons along with L-29 vortec heads? Would be a lot cheaper than the Brodix combo. The larger oval ports(larger than PP) and heart shaped 99cc comb chambers would be perfect with the correct pistons. Have block bore notched if you can swing it and recondition rods and cranks. Personally I strongly considered this build prior to deciding to get out of control with a 496 lol.

The way I look at things is this. For about 100 bucks more per set, you can have the H Beam. So in this guys case, he's out of pocket 200 bucks. What does 200 bucks get you these days? in a 34ft scarab, 200 bucks wont get you thru a Saturday of running on the lake. I am sure if you ask any of the "pro" engine builders on here, if they had a choice to use the Scat H beam, or the Scat I beam, they would go with the H beam.

I guess everyones budget is different. When I was going thru my engines, every step of the way I was faced with the dilemma of which way to go as far as parts choice/cost. I'm the cheapest bastard around, and don't like spending money. I also exceeded my initial budget. But, what I kept telling myself, is, if it meant I had to sit a few weekends out on boating, to have some stout engines, that's the sacrifice I'll make. I didn't want to cut corners by using lesser quality valve springs, weaker rods, standard head gaskets, cheaper pistons, cheaper lifters, etc. I could have saved some money by using some budget pistons instead of the JE blower pistons, kept the GM rods, used cheaper comp lifters instead of the Morel Race, comp springs instead of the Tool Room's, compostion head gaskets instead of cometics, head bolts instead of studs, main bolts instead of studs, standard drive plates instead of heavy duty, tube coolers instead of plate bellhousing coolers, the list goes on. And keep in mind everything is x2 with a twin engine.

As far as machine work on your blocks, don't cut corners there. You'll want to magniflux and psi test the blocks, have them tanked, decks checked, line hone checked, sonic checked, head bolt threads checked since in a mark iv they are known to rot away in marine engines. Your gonna need rotating assembly balanced, crank possibly polished or cut depending on its condition, pistons pin fitted, cam bearings replaced, freeze plugs replaced, and so on.

I am not trying to scare you. But I am telling you from my experiances, and many boating friends experiances, do it right the first time. The guys you see with engines that don't live 20 hours, is because they cut corners. Machine work is HUGELY important. If you have "x" amount of dollars to work with, start by investing it in a proper rebuild on the short block. Worry about performance heads and things like that, after you have some solid foundations to build off of.

The scat I beams would be way more than he ever needs. No disrespect, but I don't listen to every "marine engine builder" on here unless I have dealt with them personally. Everyone has their preference in parts. You don't see a rash of Broken rods, especially these on here or anywhere else for that matter. Spending $200 extra is likely going to just drain this guys account at this power level.

Regarding valvetrain, yes quite a few respected guys here will tell you to buy the best you can afford and that makes perfect sense. But that is the most highly stressed part of a BBC, even more so obviously in a marine application.

The problem with this site is everyone seems to recommend overbuilding everything and that's absurd. And I disagree that H beam is always a superior design. Oliver parabolic I beams are one of the all time best rod designs. Not an H beam. Most failures are from detonation and improper assembly or Broken valves. I've seen quite a few rod bolt failures at the local machine shop from high end boat builds, but never a rod just letting go because it didn't cost $600+.

Applying the spend more because it's better logic to every aspect of a marine build at this level is poor advice IMO. We aren't heading to the moon here. Again, valvetrain, couldn't agree more.

I hear you all. 450-460hp......nah, I'm looking for 500+. What are your opinions on keeping stock heads for now and upgrading/rebuilding bottom end and valve train? I know I would still have to work on heads to get those back to par. I just hate the thought of putting new valves and cam components in these heads just to switch them out for new heads at a later date. I have to put all this down on paper and calculate some ballpark figures for all the different angles. Or better yet, callig Bob.

Call bob

Trust me, a Scat I beam, is not anywhere near the quality of a Oliver I beam. I'm not gonna get into a pissin match with you on every thread.

Please show me where I said that? This isn't a pissing match, it's logic. H beams aren't logical. I speaking In terms of basic design I beam vs H beam and applying said types to this guys 500hp goal. Obviously H beams are not needed. I must be on glue.

I agree. The I beam will work fine for what he's doing. Fast forward to 3:00 for a little rpm

You have your recipes, and I have mine. its all good Heres my rect port H beamed 454's http://youtu.be/nNzqL_RJlG0?t=3m

Yeah no worries,it is all good. Different strokes! That's a sick Fountain you got there. Is that an older justin Bieber in the red shades?

That's "sommerfliesby" from Oso . He's got a 37 Active Thunder