Was anything done to the bottom end? For instance, on my 3400 crank, I had the journals turned down to match the newer V6/60 design of 2" journals allowing for running more modern/lighter connecting rods (and pistons) despite my rods being longer.
When the crank was rebalanced, it went from 43lbs down to 37lbs. I forget how much lighter the pistons and rods are...

------------------
Laughing at trolls who ask me to post 1/4 times when I built on oval track car.

[This message has been edited by lou_dias (edited 12-11-2022).]

I believe he says he is running the marine crankshaft (fully counterweighted) at 186cu in. Thats 3.6" stroke and .060 over bore. Making it a 3.0L. To run that stroke you must use at least a 6.125" rod, he is using some forged units from Scat, and the pistons are hypers for a ford application to achieve the proper compression height.

The marine crankshaft has a lot of material that stock duke cranks dont.

Edit: stroke maths out to a 3.6" (Vortec 3000 engine)

[This message has been edited by FieroWannaBe (edited 12-10-2022).]

All this talk about half filling a duke block, is that even possible?
On my Super Duty block the bottom of water jacket is the bottom of the coolant inlet from the pump outlet, filling the jacket would occlude the water inlet.

Filling the block is a common practice for the oval track grassroots racers. Oval races are not 1/4 mile races were the block is filled completely because the races last 9-12 seconds and the engine gets shut off. These guys go round and round for hours. The only thing they are cooling is the upper part of the cylinder and the heads, and that is were all the heat is trapped. Down the bore is only piston ring drag that produces the heat and that's why the "half fill" is the practice.
The one thing I've noticed is an oil cooler to make up for the lack of water cooling of the lower half of the cylinders and the oil cooler size is proportional the HP the engine is producing. So, oil quality is crucial. Why would you build an expensive engine and use synthetic oil with the wrong friction package because is cheap?
It's basically because of the ignorance of the builder or owner. DO YOUR HOMEWORK. NOT ALL SYNTHETICS ARE ALIKE.
I've never ever had a flat tappet cam wipe a cam lobe, why? I use the RIGHT oil and that includes the oil's viscosity and the right oil for the job.
I use one breaking oil, one dyno and racetrack oil and an oil to just warm the car up in the colder months. It's just common sense, but some MIT graduates (or individuals that think they know better) can't comprehend because their quantum mechanics software tells them that will not work, they have lost their human touch!

quote Originally posted by La fiera: Filling the block is a common practice for the oval track grassroots racers. Oval races are not 1/4 mile races were the block is filled completely because the races last 9-12 seconds and the engine gets shut off. These guys go round and round for hours. The only thing they are cooling is the upper part of the cylinder and the heads, and that is were all the heat is trapped. Down the bore is only piston ring drag that produces the heat and that's why the "half fill" is the practice.

My point was the common practice of half filling the cylinder water jacket up to the water pump ports on a v8, doesn't look feasible with the factory duke water pump. The cooling jackets lowest point is also the lowest point on the water pump port. You would need to tilt the engine when filling and then only cool one thrust side of the block, and that is the opposite side that pontiac recommended capping for better exhaust port cooling.

Here is a random duke picture from the web, I highlighted the water pump port, it would take some creativity to half fill the cooling jacket and keep the water pump inlet clear. Other wise there will be no coolant flow at all.

A typical V8 fpr the circle track crowd has much larger cooling jackets.

[This message has been edited by FieroWannaBe (edited 12-11-2022).]

Wow! That's not good at all!

You might try placing some styrofoam to create a coolant passage. Then, fill the block.

Afterwards, you can burn out the styrofoam with a torch.

I thought about this idea, because I used to own a Saturn with an engine cast with lost-foam.

Just an untested idea!

Edit: toluene will also dissolve styrofoam.

[This message has been edited by pmbrunelle (edited 12-12-2022).]

Here is a Duke block (with LS head), half filled cooling jackets. Its appears to be running a remote water pump.

With today's technology one doesn't have to use a belt driven pump.
https://youtu.be/_32rdmTTIGE

The water pump system I use is totally independent of engine speed. Its based on temperature whether the engine is on or off, no parasitic drag.