Are there any Chev V8 guru's in the house?

[BaronVonChickenPants]

I have a new toy for the collection and need some input as to the best way to build it.

I'll start at the beginning (skip to the end if you don't care about the context, it's a bit of a long story):
The toy is a Williams Walkabout fibreglass clinker ski boat previously owned by my brother.
In action in its former glory:
https://www.dropbox.com/s/9320or46m10d9 ... 0Party.mp4

This video was about 7 or 8 years ago and at the end of the day the 350 Chev blew a big end bearing, put a 90 degree twist in one of the con rods, which was then punched out the side of the block, smashed up the crank and cam shafts, followed by the most of the remaining push rods and con rods.

So after this he began restoration, salvaged any good ancillaries components, bought a new motor, and began sanding the hull for a respray.........then lost interest. And there it has sat for ~6 years until last week when he decided it was time to get rid of all his unfinished projects and offered me the boat at a price I couldn't refuse.

So, I now have ~85% of a fully functional ski boat in 3746 pieces in no particular order. These boats are pretty simple to disassemble and re-assemble but I'm looking for input on the best way to build up the motor.

The question:
The motor is a Volvo Penta 5.0L which is actually just a marine 305 cu in Chev, the motor was rebuilt and run in, then sold as a long block.

I have all of the usual ancillaries, brackets, alternator, starter, etc plus the marine exhaust manifolds and a Holley 600cfm vacuum secondary carb.

But I have no intake manifold or ignition system.

So what I am looking for is advice on the best components and tuning to achieve fuel efficient performance and reliability.

The previous 350 chev gave good performance and we could have a good weekend with fuel left over in the 60L tank but the hull can not be insured with anything larger than a 308.

My research so far has been a little bamboozling due to the long run and variations of the 305 chev, the ran from 1966 to 1996, can be found in configurations from 130hp to 350hp, with everything from 2bbl carbs and points dizzy's up to supercharged MPFI systems.

Filtering through all this has led my to an Edelbrock Performer manifold such as this.

And a Mallory HEI distributor, such as this, but I am unsure if this dizzy needs to be controlled from an ecu or something simpler, either way I do not know what additional components would be required for the ignition system, other than plugs and leads of course.

So....ideas? suggestions? advice? comments? criticisms, constructive or otherwise?

Thanks,
Jordan.

[Rodeo4jake]

G'day mate
I have put together quite a few GM V8s in my time & can give you some of my opinions about your questions.
Mallory Hei is a simple stand alone electronic ignition so ya just need the dizzy & coil unit. You can usually buy this all in one kit for a chev. Should be fine for your application, as will the Edelbrock manifold.
Carbys can be tricky on boats, from my experiences do not get a Holley. They use heaps of fuel & the design of the float bowls is such that they don't like not being dead flat. Due to this many people have trouble with them in boats & when they decide to stick a chev V8 in there 4wd & go off roading. I would suggest getting a quadrajet carb off an early 308 or Chev,both will work. You will potentially need an adapter to bolt these to the Edelbrock manifold though.
Also pay special attention to the sealing of the valley when you fit the manifold. As deck heights in engine blocks & heads can vary, often the front & rear of the manifold ends up to far from the block for the gaskets supplied. Because of this I used to leave the cork gaskets out & just use blue rtv gasket maker. I found this to work long term on more than 1 engine I built.
Hope this helps, sounds like a fun project. Boats are great to work on I reckon.

Cheers Jake

[tambox]

I used to be involved with dyno tuning V8 ski boats, the quadrajet is a very adjustable carby and is more fuel efficient than a Holley.
Dyno tuned is better, but it costs, EFI is better again, but it has to be dynoed to work well and it costs even more.

As Rodeo4jake said, watch the gap under the ends on the manifold. Its worth checking the port aligment/size as well. A bit of time with a die grinder is worthwhile and dont forget to make sure the gaskets are ported as well. We have had to get manifolds surfaced to fit some motors properly, but that was rare.

The mallory dizzy is good.

You will need an spreadbore adapter to fit a quady on that manifold.
Standard manifolds work well, although not as pretty.

[BaronVonChickenPants]

Thanks fellas.

The Holley is what came off the exploded 350 Chev, it had a wedge adapter to keep it level. I'm pretty sure he had a few quadrajets kicking around as well, will hit him up for one of them.

Is there anything additional required to run the Mallory, like some sort of trigger when to fire or is it all internal within the coil pack and dizzy?

What fuel pump should I use? I would prefer to go electronic but have no idea what sort of flow rate I require, is there a significant advantage to the electronic other than the initial priming of the fuel lines?

Jordan.

[tambox]

There are many options with the Mallory distributers, the one you list is not marine rated. Are you running an engine cover?, how much water will splash/spray around/into the boat?
Sometimes marine rated is an overkill, sometimes is safer to have the marine dizzy, you may not need full marine rating (expensive), but one that will suit what your requirements are.
I know thats not very clear or possibly helpfull, it depends on boat setup and how it is used as to what you need.

Electric fuel pumps are more controllable than manual, ie turn it off instantly if required (leak) and they don't drip oil insde the boat:D
Flow rates will depend on motor, cam, tuning and RPM. If its not a high revs motor, match or exceed the standard flow rate. Pump suppliers can usually cross match.

If you are going to get a used quaddy, be carefull. Ones that have been used with LPG often get bent. People bolt the mixer adapter to the carby using the air cleaner lid bolt. This attaches to the centre body of the carby and the weight of the LPG suff, bends the centre of the carby. This causes air/cross bleed gaps and makes it impossible to set up correctly.
If the bending is only minor, there are ways to fix it. To check, you need to take the base off the carby and straight edge the middle body that attaches to the base.

[BaronVonChickenPants]

I've grown up around chev powered ski boats, so understand the abuse the suffer and maintenance they require, but I have never done a ground up rebuild like this. We're basically talking bare fibreglass hull, a long motor sitting on a shed floor next to a pile of related pieces and I have to turn it into a boat.

In this boat the dizzy is under an engine hatch and would be no more exposed to the elements than in a cars engine bay, a little more salt exposure but nothing that I'm really concerned about, starter motors and alternators have far more trouble than dizzys.

I believe the motor has a "marine" cam tuned for a little more bottom end torque than normal.

Due to the hull design I have a top speed of ~55mph, it just becomes unstable above that. The prop that's fitted gives good performance and roughly a 100:1 rpm:speed ratio, ie: 3,000rpm = 30mph.

Our main interest is casual skiing and wakeboarding, which gives us a normal speed range of 22-35mph, but I don't mind the occasional blast at full tilt either (honestly, who doesn't? )

So we have a mild torquey cam, Mallory HEI dizzy, Quadrajet 4bbl carb and a practical rev limit of 5,500rpm, I'm thinking any fuel pump over 100gph is just going to be excessive, does this sound about right? Something like this? is 6psi enough or would 14psi be better?

Will this require some sort of fuel pressure regulator and return line or will the pump stop when the float valve closes the inlet on the carb?

Sorry about all the questions, I just want to get this right and do it once and have reliable fun.

Thanks,
Jordan.

[tambox]

6-8 PSI is normal and will do.

If you get a self regulating pump, it does it all.

I have not done this for years and not aware what products are available now days, but the internet makes it better (or worse as there are so many options)

[El_Freddo]

We've got (I presume) one of these dizzy's on our 350 chev powered boat. It also runs a 4 barrel Holley carb. The dizzy transformed the engine's starting ability and resolved other issues we had with it back then.

We've not looked back, and while Dad didn't want to have to outlay some coin I think he's very glad we did. It started second go after almost three years of no use. We had to replace an O ring on the fuel system but that was it. Further on the dizzy, I don't know if they have special spark leads as the top of the dizzy is the same as the spark plug head, so only one end is properly secured But it all works so that's all good.

The fuel pump is mechanical, we have an electrical pump to prime the system (god-send!). The only real issue we have with the holley is that it seems to flood easily if you don't do the "correct" starting procedure. It seems to go alright on the juice after a heavy day's skiing Looking forward to getting it out again

Cheers

Bennie

[pitscars007]

Just my two bobs worth - I reckon the marine cam would give peak torque around 2500 rpm - the prop pitched to ski speed and maximum torque is going to give you the best economy - more pulling power - engine will last longer - cheers

[BaronVonChickenPants]

So after an evening of sifting through the various pieces and decoding casting numbers I have found the following:

• I do have an intake manifold
• I have a complete engine with the following history
  • Built for fitment to 1981 Camaro - rated 130 HP at the wheels
  • Rebadged as a Volvo Penta AQ225 and fitted to a 23 foot bayliner - rated 225 HP at the flywheel
  • Rebuilt again 2010 as Volvo Penta AQ225
• My brother had turfed all of his quadra's as they were deformed and/or corroded beyond repair
• All of the push rods are missing (didn't see that coming)

I believe 225HP should be adequate for my requirements, so at this point I don't plan to do anything other than:

• Rebuild Holley 600
• Fit Mallory HEI dizzy and coil
• Fit ~100gph self regulating electric fuel pump

This should hopefully mean with minimal effort I will have a simple and reliable motor for under $1,000 including various gaskets, push rods, spark plugs, leads, fuel hose, etc.


Thank you to everyone for your input and assistance.



Now to sort out the rest of the restoration.....