dumb Q but can you make a 289 into a 5.0?

The machine shop told me that the 28 oz balancer can not be used on a 50 oz motor the ratating assembly will not ballence out, because one is internally ballenced and one is externalled ballenced

Lswhat said:

The machine shop told me that the 28 oz balancer can not be used on a 50 oz motor the ratating assembly will not ballence out, because one is internally ballenced and one is externalled ballenced

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they're both externally balanced, that's why the balancer is outside the engine .....so long as the balance on the flywheel and balancer match, you'll be ok. If I remember correctly, all 302 cranks are 'neutral' balance. The counterbalance on the balancer and flywheel is to absorb shock loads from the engine firing. The only reason they went to 50 oz was for slightly less vibration to comply with modern NVH standards. The only diff. between 289 and early 302 cranks in the stroke(2.87 vs 3.00), they only difference between early 302 cranks and late model cranks is the late models have a one-piece rear main seal. That means all the balancing stuff interchanges, so long as the imbalance of the balancer and the flywheel match.

To quote a very reputable book entitled "Ford Windsor Small Block Performance" by Isaac Martin(pages 24 and 25), "There's one important thing to remember about dampers and flywheel interchange on the 289/302/5.0L. First, Windsor engines are externally balanced. External balance means that balance weight is added or subtracted the damper or flywheel. In 1981, Ford made a change in the engine balance factor, going form 28.2 oz/in to 50 oz/in specification. While dampers and flywheels interchange, don't mix pre 81 components with post 81 or the engine will suffer an imbalance. In other words, the flywheel and damper have to both be earlier than 1981 or after. Don't mix them."

Make sure to use a better machine shop in the future.....

well thats what i thought too but they explained to me that it was how the crank was actually balanced not having to with thebalncer or flywheel im not saying they are wrong but it deffinitly would have made my life easier if thats the way it is and not the way they said.

You CANNOT use a 28oz/in balancer on a 50oz/in balance motor. It will shake itself to death ( and rattle your teeth too) The cranks are completely different between the two in terms of the counterweights. The 50 oz/in has much smaller counterweights than the older 28 oz/in crank.The change had nothing to do with NVH standards, it was done as an economy move for production cost's. Also, the 5.0 designation came about in 1979 when the roller cam motor was just a pipe dream. He can use the 50 oz/in balancer by using a later model timing cover, the covers and water pumps were redesigned in 69 or 70 to the drivers side intlet for the water pump. All 289's and 302/5.0's are externally balanced.

hmmm, this has spiked a desire to do some additional research.....

I'm not trying to advertise for Mustangs Plus, But the easiest (maybe not the cheapest) way to do a 5.0 conversion is call mustangs plus. Ask them what to do and order any speciality parts. They have walked hundreds painlessly through it. including me. Thats my 2 cents anyway. Goodluck

D.Hearne said:

You CANNOT use a 28oz/in balancer on a 50oz/in balance motor. It will shake itself to death ( and rattle your teeth too) The cranks are completely different between the two in terms of the counterweights. The 50 oz/in has much smaller counterweights than the older 28 oz/in crank.The change had nothing to do with NVH standards, it was done as an economy move for production cost's. Also, the 5.0 designation came about in 1979 when the roller cam motor was just a pipe dream. He can use the 50 oz/in balancer by using a later model timing cover, the covers and water pumps were redesigned in 69 or 70 to the drivers side intlet for the water pump. All 289's and 302/5.0's are externally balanced.

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This is true, When I was building my 331 I asked the machinist what balancer it needed and he said it was a late model motor so it took a 50oz. After having my teeth shook out I called Eagle and they said that if the rotating assembly had been balanced with a 50oz. the crank would look like swiss cheese, because they would have to take out so much metal from the crank in order to get it balanced. Eagle said use the 28oz. I took everything back apart and put in the 28oz. flexplate and balancer and it runs smooth now. The fact is the machinist did not know what wieght balancer Eagle sent with the kit. He just thought it was a 50oz. Never will I go back to them. Every rotating assembly must be balanced using the 50oz. or 28oz. they can not be interchanged.

Well, I learned something from this. Like DHearne said, the late model cranks have less material on them(nearly 3 lbs. less), so they have to make up for it by adding weight to the balancer and flywheel. Sorry for any confusion I may have caused. If using a post 81 crank, you must also use the 50 oz balance equipment.

65stang289 said:

LOL super Dave I understand what you mean. I just like looking at the back end of my car and it says 5.0 HO. What is a 289 a 4.6 right or not? SO I can just get a wrecked 5.0 and switch it back to a carb motor and leave the roller cam and rockers in it then? I want a 5.0 but with a carb not fuel injections. What would you all do go with the carb setup or the injection?

Thanks for getting back to me on this.

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My '65 is a 5.0L powered car. Engine looks like classic 289 owing to the fact that the timing cover, water pump and engine accessories are 289 components! Yes, it has a carburetor (Holley Street Avenger/Weiand) sitting on top instead of the fuel injection! No, the engine doesn't care if its fed by EFI or a carburetor...either one works. Is it a better performer than the 289 it replaced? Yes, I had an "A" code 289 and the 5.0L is a step upward performance-wise (much more like "K" code 271 hp 289). It also has better flowing heads, manifolds, and a cam grind that makes use of it. Does it all fit and bolt together? Pretty much...but there are some things you have to adapt to make work...its an easy swap by swap standards.