I picked up this float back in June.  It is my first jet boat.  I had it shipped all the way from Cali to central PA sight unseen.  It arrived and looked awesome.  However, when I pulled the valve covers, I noticed five exhaust valves stuck open and after fixing them, I still saw no compression on multiple cylinders.  I decided to call this year a wash and rebuild it.  It was a gen IV 468 bbc with a mooneyham 671 blower.  Berkeley 12JC pump with A Agressor bronze impellor.  Jensen's engines out of nescopeck PA did the machine work.  I was going to have someone build it for me as I have never built an engine from the ground up (and mainly work on motorcycles and diesels), but it went almost four months and the guy never even touched it.  I decided its now or never.  Sink or swim if you will.  Here are some pictures of the boat and build so far.  I have done so much to this and have a decent amount of money in the upgrades and parts its insane.  I have 105 hours into the engine build alone so far and counting.  I am double checking my double checks so I hope it all works out.  I am looking to get it dynoed in the next month or so.  My fingers are crossed.

Parts list (used to be hydraulic flat tappet with a baby cam and 1:1 pulleys):

SRP pistons (calculated 8:1 compression now)
Total Seal file fit rings (gapless 2nd ring)
Forged shotpeened rods
Scat forged balanced crank
Clevite bearings
Melling m77 oil pump
10 Qt dooley oil pan
Gen IV bbc block (now 472 cubic inch)
World Ind. Merlin 1-043C 119cc iron heads
Cometic Stainless MLS 5 layer .070 headgaskets
dual valve springs with dampers
Comp 1.7 ratio roller rockers
Comp .135 wall 3/8 pushrods
Crower solid roller lifters
Comp 11-771-8 cam (242, 248   .646, .653    110 lsa
Blp 3 piece timing cover
Rollmaster torrington timing set
ARP EVERYTHING
MSD 6M-2L, blaster 2 coil, and pro billet hei distributor (locked out, 31 degrees BTDC advanced timing)
Moroso Ultra 40 8.65 wires
NGK heat range 8 plugs
2.5% over pulleys (40 tooth 1/2 pitch upper and 41 tooth under)
Jomar Professional stud girdles
Basset coated headers
Dooley air scoop
Two side mounted Holley 850 four barrel carbs
Weiand carb adapter and intake manifold with burst panel
Edelbrock mechanical fuel pump (7 psi)

Main bearing clearance is .033
Rod bearing clearance is .028
crank endplay is .0045
cam endplay is .004
Ring end gap is .033-.034
472 cu. in.
8:1 comp ratio

Here are some pictures!

I was testing to see If I knew how to post pics.  Here they come (hopefully)

It arrived:




Removing the Cali Registration numbers:












Re epoxied the suction plate:





Stuck valves:

Safecraft extinguisher:

Before and After:









Buffing polish and ceramic coat:











Custom towels haha  I'm insane:

The build begins:

Put the manifold on and then noticed the new tall fabricated valve covers didn't fit by millimeters (the old ones were M/T fined covers that had stamped edges on them and fit).  Had to take it all apart:



Forgot the arp oil pump driveshaft like an idiot (my first time doin this!!):









Lockin 'er out at 31 degrees BTDC.  Hoping to run pump gas with my comp ratio, but I have AV Gas at my disposal if needed:









Making the transport table/cradle for the dyno:

The picture are great!  Love the boat and the effort!

Nice job, I like your choice of scoop way better then the one that came with the boat. That boat should haul ass. Good luck with the rest of the build


Sent from my iPhone using SoCal Jet Boats

Sent from my iPhone using SoCal Jet Boats

Silly Question, but does it matter how the belt is routed?  The way I have it is how it was when I received it.  However, I see almost all other blown engines route it toward the outside of the idler pulley.  If I do that, it is kind of close to the fuel line, but I think it would work that way too.  Opinions?    I am at a stand still until I can get to the dyno.  Only thing that sucks is, the dyno needs to pull the throttle backwards and my setup is a hard cable that pushes up on the "wheel" on the back of the carbs/blower.  I was thinking of rigging up a mini pulley on a bracket and then crosby clamping a cable to the "wheel" just for the dyno.  I didn't want to change my whole setup just for the dyno

Thank you for that video. It was very informative. I currently have it set to 1” of slack. I hope that is right on the money.

I just hope I can get the engine going on the first try and get it broken in, carbs tuned, timing set perfect and then..... figure out how I’m going to somehow get some antifreeze in the block so I don’t completely ruin all my hard work over winter

The blower shop says 3/4"- 1" cold which is 1/4" hot.  Are you saying to set it 1/4" cold?

TBS instructions:

 "Allow ¾” to 1”of side-to-side movement on the straight (long) side of the belt. With
the engine at full operating temperature you should have ¼” of side-to-side movement.
*Note: Do Not over tighten the belt. Doing so can cause severe damage to the crankshaft and drive components."