mcollinstn

If you're starting from scratch, a 632 benefits from a "raised cam" block to give better clearance for the big stroke you'll be running. You can do it with a standard cam location, but it's easier and less hassle when you use a raised cam block.
Be aware that your head choices include options that have raised or angled exhaust flanges, which will have some effect on the overall width/height of your exhausts as installed in the boat.

Otherwise, it's pretty much dimensionally identical to any other talladetalldeck big block chevy.

Brad Christy

McCollumsTN,

Cool. Thanks. This is exactly why I at as Ted th is quest here. So, on to the next….

I’m also going to be height constrained. I will not be able to move forward if I cannot stuff this thing under the sundeck. As far as I can see, the big obstacle here is the intake manifold. As with the existing 496, I would plan for EFI, and would like to use a front throttle body intake. All the top TB options see seem to appear to be way too tall. I’ve found several options I like, but, so far, short of a handful of custom shop offerings ($$$$), all I can find are for small block builds. Any suggestions?

We’ll most likely get to a full parts list before this is done, but let’s get this one cleared away for now.

Thanks. Brad.
(937)545-8991

hogie roll

No perfect solutions for what you want to do.

This is closest and it’s only for a 9.8” deck height block I’m pretty sure. A 632 needs a 10.2 or 10.4” tall deck block ideally. You’d need spacers.





The next easiest solution would be to find a tall deck tunnel ram that fits under your height requirement and have a custom lid made and hole cut in the front for a throttle body.

The nicest and most expensive solution is custom fabricated manifold like Kwrights.

If you don’t have to have the tall deck, you can fit 565-582in^3 in a 9.8” deck height block.

Brad Christy

Hogie,

The block I’m looking at is a 10.2” deck with .400” high cam position. Perfect for a 632ci.

Kinda thinking about fabing a manifold together myself. I do have the capacity and the resources to do it. I like challenges like that, and it would give me the opportunity to make it more my own. Any idea what all the “extra” holes are in that intake are? The injector ports I get. The rest, not so much… Extra injector ports? MAF sensor? ???

Thanks. Brad.
(937)545-8991

compedgemarine

I would think the biggest problem would be that no bravo based outdrive is going to last with the torque that a motor that big would make.

Brad Christy

Compedgemarine,

I spoke with George at AADS a while back, and he seemed pretty confident. But I get it. Something else to consider. I will, for sure, readdress that conversation with him before moving by forward.

Thanks. Brad.
(937)545-8991

F-2 Speedy

If you dont want to run a trans, then the Imco SCX is probably the strongest bravo style drive, projects are like the bunny it keeps going, why are you stuck on a 632 ? whats your HP goal

Brad Christy

F2,

850 or so, I guess. More if I can get it (duh). I’m not stuck on anything, I just figured the 632 was about as big as one could stuff in the space I have, and I could probably build it for less than I could a smaller Whipple engine, assuming I could get it under the sundeck. I know I can’t do much with the 496 without addressing at least the pistons (Merc tells me the S#s indicate forged rotating ass’y except the pistons).

This whole fantasy started when we bought the PowerQuest. I love the boat, and have no intention of letting it go. But, I was all excited about owning a boat with a blower motor, as that’s what a grew up skiing behind. I figured the 496HO/ProCharger combo, supposedly rated at 615HP, would work well enough as a muscle boat and a pleasure/family/ski boat. It has come to my realization that the ProCharger is not really all that it’s cracked up to be, and the boat really struggles to pull a slalom out. I’ve since propped down (from 28 to 26”), and it’s a much more manageably planing boat, but I lost 2-3MPH in the swap, and that pissed me off.

Since I’ve always been a GoBigOrGoHome kinda guy, the NA 632 seemed the perfect solution. 🤷‍♀️

Thanks. Brad.
(947)545-8991

ICDEDPPL

First that`s going to destroy your outdrive, I don`t care what George says, bravo gears are small and you can`t change that fact.
Secondly, rod angles and whatnot , all that is $hit in stuff over 600ci.
I don`t like this plan at all.
Sorry, not sorry.

Brad Christy

Ded,

Don’t be sorry. That’s what I’m here for. If a 572 or whatever is the ticket, that’s what I’d build. God knows I’m the student here.

The ONE thing I don’t want is a scatterbox looking for an excuse. The plan would be to do the build, do the swap and sell an extremely low hour 496HO/ProCharger combo to recoup most of the cost. If the damned thing blows up, just on principle, I just might get buried in the boat. Same with the outdrive. What I want most of all is an ultra reliable boat that runs strong. I know it can be done. It’s just a matter of forming a plan and working the wrinkles.

George doesn’t use Bravo gears (at least, that’s what he tells me). He machines the casings to accommodate larger gears, shafts and U-joints. His “Stage 1” is supposedly good for 700HP for 200 hrs, with a two year warranty. I do get it, though, and, if another $15K is in the cards to make this all fly, the wife is gonna put her red headed clamps on it pretty quick. It’s already going to be hard enough to convince her we “need” the boat to go any faster than it does now. She didn’t grow up on an 85MPH, 21’ semi-flat bottom day cruiser, like I did. 67 already kinda has her white-knuckling it.

Thanks. Brad.
(937)545-8991