Just ran across a 1972 17' regatta jet boat with 402 and Berkeley jet for $125.00. The owner told me that the motor was blown and needed to be rebuilt. I have notice that all the boats i have looked at on this site has the big blocks powering the jet. Will a small block work behind a jet drive?

The 402ci was also a BBC.

I have a 383 small block and it turns a new A impeller 5K.  The hardest thing you will encounter is finding the exhaust for it, especially if you are looking for OT headers.  New they are pricey and available, used very hard to find since they are uncommon in jet boats.  The bellhousing will be the same, you'll need a small block front mount if it's a 4 point mount system, if it's a 3 point in the boat now it might work with a small block.  I'd line up the parts before you commit to that, it might be just as cheap to slap another big block in there, that stuff I see all the time. 

Generally the smaller (16'er's) had the small blocks . It'll be alot cheaper to work with what you already have also .

-beerjet-

BBC and SBC use the same bell housing.

That could be a problem.

Very little, if anything will be usable for a BBC or SBC swap.

I was pulling the motor apart this afternoon and noticed it is not a 402, it is a 403 buick motor.

Far more likely that it is an Olds 403. Olds has distributor behind the intake. Buick had distributor in the timing cover.

Posting pics would be helpful to identification.

I've got a rear motor plate that gets used with a stock "Velvet Drive" transmission bell housing if needed, but dont have a housing. If you need it, I don't. Its bead blasted and in pretty good shape (aluminum).

$20 (see you don't even have to make the standard So Cal offer )

Camera blew up, here's a drawing.

Thanks Tom,
This is the first jet boat i have played with and i just would like to take my time and get all of the right parts together. I have all of the parts to the boat, at lest i think. I paid $125.00 for the boat and all of the parts that was in it. The guy i got it from, took it apart so i hope i have all of the parts. I was mistaken about the motor that came with the boat it is not a 402 bb it seems to be a 403 olds. SO the bellhousing is not the same, as for the exhaust. I having a hard time find headed for a 350sb without paying a left nut for. By the way this might sound like a stupit question but does this motors have to spin the same as a normal engine? I heard that a marine motor rotates backwards?
I will try to post same picture when i learn how to do it
Radracer

Man That is so SWEET.... Is that a white water boat?

I forgot to add that that engine was in the process of being installed (during the boatshow) when these shots were taken, I believe due to a spun bearing. That is why there are no wires or anything on the motor, the boat show was two days before the race...

Here's Merv's boat in action, this is the 2008 Worlds in Ore. 8 miles upriver from the Pacific (between 75 and 85 mph) keep in mind the water is moving 5-7 mph.

These guys typically see water thats about 6" or so, the engine often pics up rpm due to the cavitation from the rocks