Welp.... That build didn't last long.. Boat was running great all 4th of July week out on Lake Lanier. Last day of vacation, I decided to take one last ride before putting her away. Got out on the water for a nice ride, decided to hammer on her a bit and boom...

Motor shut off, I came to a halt, motor is locked up... I'll be pulling the engine and disassembling to see what happened. I heard something come apart in there when it died so i'm assuming I'll find a broken piston like last summer.

I'm assuming that the vortec heads paired with the xtreme marine cam was too much for the factory cast rotating assembly? Should I have this motor put back together with forged parts if the block is salvageable? I'm hoping my vortec heads and cam are still good. Would be nice to just rebuild the shortblock!

I want to build something that will hold together with this power this time. Any suggestions? Thanks in advance!

Correct.
Have been running a stock 27yr old Merc 260hp shortblock for almost 10yrs now with Brodix heads, BG 650 Carb, eddie marine Exhaust w/short length risers, and extreme EFi roller up to 6k rpm.

But I tune and rig also.
Removed antisiphon valve
New rubber line to fuel pump
holley mechanical pump
full flow fittings
Strong pushrods
Good valvesprings
Good oil
Very good GM Performance lifters

Blah blah blah.

Boat went from mid 50's to 68 and change. Now 73 With alpha SS with my 3+mph reducing mufflers that I have not removed for Alpha SS testing yet. And have to play with props again since 6k-6200rpm is past peak hp for a 218/224 at .050" cam with .565" lift or so.

BTW: I beat the crap out of it routinely and the outdrives (regular Alpha and Alpha SS) keep on ticking, Secret is not to shift at high rpm. Try to keep it under 800rpm for shifting.

I have helped many other people with small blocks in light boats and Alpha's and their experience is pretty much dead nutz even with mine.

#itsasmallblocknation

Sorry to hear about the motor. Teardown will tell you alot. Was A/F ratio ever checked? Plugs read? Forged is always better for rebuild. Stock SBC shortblock is fine for 400hp/6000rpms when tuned right. Ran them for years at that power level. Dump the quadrajet. Make sure you fuel system is overkill.

Copy my last SBC build. It is bulletproof and will run!

385ci SBC Engine FS


SB, Good to hear the SS is still kicking a**! Always liked that drive. Numbers look good!

Thanks for the reply's gentlemen. I'm puling the motor this weekend and will report back with my findings and some pictures. I'm going to take the motor to Lamar Walden Automotive here in Atlanta and have him put something stout together for me and tune it.

Man tell me about it... I read the original boater world review from way back in the 80's and the article said right at 60mph out of the box.. I'm stumped as to why I can't get more speed out of the boat. Obviously the motor never was tuned correctly so that surely plays into it but before any of the mods with the factory 260hp engine and captains call the boat would top out at 48 mph gps wot..

I'm curious if the alpha is geared wrong for the boat.. I did gain 9mph after the heads, cam and intake but still, you'd think I'd be well into the 60's maybe close to 70 wot... The difference in power across the board was tremendous. The boat pulls HARD to top speed, just hits a wall at 57 @ 4400-4500 RPM and won't spin higher..

The cam is advertised to make max power at 5500 rpm... That would probably get the mph where it should be! 21pitch mercury vengeance SS prop...

Thoughts?

MADDENING!! I've had the boat since 2011 and still haven't figured it out.

Fuel or ignition.

Start digging and finding the issue.

==============================
Few quick things and then keep digiging from there:
- Rubber fuel line from tank to the seperator/filter. Long over due to be replaced if not. use 3/8" marine fuel line.
= While your there check the operation of the antisiphon valve amd also check to see if some peice of garbage is in there.
= I worked on an 88 Wellcraft last summer that had a cork fuel gauge float that came all apart. Much of it got in the fuel filter/seperator - a wad of it was stuck at the fuel line pick up. I about crapped myself. No, scratch that, i did crap myself.
- If TBIV / EST / or EFI Check for 12+ volts at your ignition coil. if you have an electric choke or hour meter hooked up right there, hook them up to some other Ign+ connection.
- still doubt the Quadrajet is tuned right or it is not flowing enough fuel. You need to be able to check this yourself. Wideband / plug reading / changing jets/rods to see if any better or etc. wideband the easiest way typically for some.

Thanks for all of this!! Much appreciated, I will get this damn thing fixed, tuned, and running right! Should I go ahead and dump the quadrjet for something new? Edelbrock or Holley perhaps?