Hey fellas-
This post is just for constructive criticism and different ideas. I’d like to share my parts list for my build and see what your thoughts are

489
Twin VS 7875 with a raw water intercooler (boat)
Trying to fall into the mid 9’s static compression
ProMaxx 317 heads, no porting 2.25/1.88
Hyd flat 224/228 @ .050 .540/.540 112
Weiand Track Warrior 4150
CSU blow through
I’m still deciding ignition and fuel system. Leaning towards the Aeromotive belt pump for fuel.

Jet boat build with open exhaust, raw water cooled and chilled and 6-6200 max rpm. I don’t see me being much passed 10-12lbs of boost. 15psi max.

1k-1200 fwhp is all I need, actually beyond what I need.

Am I on the right track? Hopefully I am...I have all this stuff!

(Yes I have all the right stuff in my boat and jet pump)

Thanks for the imput guys!

 

Overall the combo looks pretty decent. You're potentially leaving a *lot* of power on the table with your current camshaft, but your current camshaft will still work. There's nothing wrong with using a hydraulic flat tappet grind; you could just afford to be 20 - 30 degrees larger @. 050" and spread the LSA to 114 with the increased duration in order to achieve your power goals. I'd be really, really surprised if your current camshaft got you to the power level you're expecting, particularly at only 10 - 12 PSI of boost pressure.

What brand and/or material type are the exhaust valves in your ProMaxx heads?

 

Thanks for the reply-
My camshaft is sitting on the shelf in the shop and I have no problem buying a new shaft. Hyd flats are cheap

My heads are bare right now. Going iconel on the exhaust for sure. I bought them bare due to 1-the deal I got and 2-I don’t trust any head manufacturers, I wanted my shop to assemble them and match parts.

 

Sounds like you have a really solid plan! Everybody has their own preferred camshaft manufacturer(s), but for your project I would recommend getting hold of Cam Motion or Crower. In my own personal experience, both companies have a very solid understanding of what a BBC like yours needs for valve timing. I don't know if Jerry is still with Crower or not, but if he is, he would be my go-to for a cam for your type of build.

 

I’ve been contemplating on having a custom grind done. Seems the $100 or so more is/would be worth it in my case.

Thanks for the help!

 

I know nothing about Jet Boats. That said, the combo looks good. The only thing I would be skeptical of is the cam. NOt only is that one small for your gaols, but the flat tappet might cause concern for me as well. With the heads you've got and ROM you want to run, you'll need a pretty good spring. My concern would be the flat tappet living under that much spring at 6500. If you can go rooler, I would. If not, I would contact a cam mfg and get a custom grind and springs to match.

 

Those are definitely questions I have. I understand the spring pressures are needed for boost. One of the “many” reasons why I’ve posted here to get some feedback from you turbo guys

 

When I started this plan 2 years ago, it was a budget build and trying to use as many parts that I already had.

The two year older me laughs at that guy regularly.

So...that being said, IF I take the plunge into roller valve train I really do feel a custom grind is they way to go. It makes no sense to me to spend that kind of money and not have exactly what I need...for a few hundred bucks more in a shaft.

 

NO, not to me. If you go roller, then an off the shelf grind will easily get your HP numbers. FWIW, I think and easy 200hp is to be had with an off the shelf roller vs your current cam.

 

Good to know. I’m doing some research as we speak. There’s always that Comp 652 lift solid roller that a lot use. Going to keep digging

 

If the lifter bores are in good shape then I personally wouldn't sweat using a flat tappet camshaft, but that's just me. There's been a couple turbocharged flat tappet BBC's running around locally in my area for quite a long time without any valvetrain failures, and that turn quite a bit more RPM than the projected 6,200 RPM ceiling of the combination in question. One of them was in a jet boat and had an Engle custom ground solid flat tappet cam. That engine eventually ended up in a car with all the same stuff as in the jet boat, and had quite a few years on it. The other was in a car with a Crower custom ground solid flat tappet cam and had no issues.

Since you're building from bare heads, you can lighten up the valvetrain some which will reduce spring pressure requirements. 8mm valve stems, tool steel or titanium retainers, and beehive valve springs will all go a long way towards improved valvetrain stability and longevity, particularly with a flat tappet camshaft. You can also groove the lifter bores or run direct-oiling lifters in order to increase the amount of lube oil available between the camshaft lobes and lifter faces.

All that being said, Disney Lincoln isn't wrong, either, and a roller valvetrain will absolutely be worth some power. If you do go roller, and you're going to stick with a hydraulic valvetrain, use Morel lifters. Those are the only hydraulic roller lifters worth using in a BBC. Of course, opinions will vary, but you'll never go wrong with a Morel lifter.

 

Very good info. Surely something to think about. My engine builder is very good with flat tappet stuff due to being a very big in the rule restricted stock car stuff. He’s fond of the Delco lifter with the hardened face and has discussed with me about oiling etc...

I guess I’ve got to choose a path, it ain’t gunna build itself!

 

I forgot to mention... MSD Programmable 6 ignition box and their blue HVC II ignition coil will cover all your bases for an ignition system. You can use pretty much whatever for a distributor since it will be locked out when used with the Programmable 6.

You can utilize a MAP sensor with the Programmable 6 in order to build a boost-sensitive timing curve. This set-up works extremely well, and is user-friendly.

Also, depending on the proximity of the fuel tank to the engine, a cable-driven fuel pump might be a nice option to consider, too. Waterman has all the components necessary to install a cable-driven pump. Of course, if the fuel tank is close to the engine then that's a non-issue.

 

One other thing... if you decide to stay flat tappet, you can have the camshaft nitride-treated as well. Nitride treatment will improve the durability of the camshaft quite a bit in terms of potential wear on the lobes.

One thing you have in your favor for a flat tappet cam is the fact that the engine will be in a boat, which means fairly steady states of elevated RPM during usage. This helps ensure plenty of splash oiling to the cam lobes and lifter faces. Idle time will be minimal, and that's when most wear occurs.

 

http://www.compcams.com/Company/CC/cam-specs/Details.aspx?csid=451&sb=2

Not sure why the link won’t work

 

241/247 @.050, .646/.646 112 LS

This Howard’s solid roller caught my eye

 

If you're wanting an off-the-shelf roller grind, I'd take a look at the following options:

~ Crane part number 139691 (hydraulic)
~ Crane part number 138781 (mechanical)
~ Erson part number E120340 (hydraulic)
~ Erson part number E129870 (mechanical)
~ Howards part number 120345-14 (hydraulic)

 

That Erson Mechanical is interesting