3 bolt to 4 bolt harmonic balancer swap

Bossman27 · 08-26-2009, 06:18 PM

Hey all, I have a question. I have a 1965 289 with a 3 bolt 28oz harmonic balancer, I believe it's 6 3/8" in diameter. I want to buy and install a new Jegs SFI approved harmonic balancer as it's a lot higher quality balancer and can withstand a lot higher RPM. My problem is that Jegs only sells the 6 3/8", 28oz externally balanced balancer in a 4 bolt. I have a two groove, 3-bolt pulley on the crank right now. Do they make pulleys that will swap over to this new balancer and still have the correct spacing for my belts and are the correct diameter? If so can anyone shoot me a link? As far as I know this is the stock 289 crank pulley that came on the motor new if that helps out. Thanks.

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Gun Jam · 08-26-2009, 07:03 PM

Just get the one from summit. Its also SFI approved i believe and installed with no BS or mods of any kind.

http://www.summitracing.com/parts/SUM-B64269/

I think that's the one I got but I dont remember it costing that much??

-Gun

Starfury · 08-26-2009, 07:29 PM

You don't need an SFI approved balancer unless you're racing a lot.

I'd recommend a non-SFI Powerforce balancer. It has both 3 and 4 bolt patterns on the front and is available in both 28oz and 50oz imbalance.

2+2GT · 08-26-2009, 09:11 PM

Quote:

Originally Posted by Bossman27

I have a two groove, 3-bolt pulley on the crank right now. Do they make pulleys that will swap over to this new balancer and still have the correct spacing for my belts and are the correct diameter?

Nope. This question comes up constantly. The 3-bolt system had an entirely different offset than the 4-bolt system.

ky · 08-27-2009, 03:59 AM

i was also wondering about this too.

i want to go with a serpentine belt system on my engine, but they only seem to come in a 4 bolt pulley for the serpentine. i just need a 3 bolt crank pulley, alt pulley, and water pump pulley but i cant find em

2+2GT · 08-27-2009, 06:39 AM

i want to go with a serpentine belt system on my engine, but they only seem to come in a 4 bolt pulley for the serpentine.
Why? It won't make the car run any better.

i just need a 3 bolt crank pulley, alt pulley, and water pump pulley but i cant find em
They are available new from any Mustang vendor, such as Glazier Nolan.

Bossman27 · 08-27-2009, 08:52 AM

Ok looks like I'll spend a few extra bucks and go with the Summit balancer that will still work with my 3 bolt pulley. Thanks for the responses!

ky · 08-27-2009, 11:58 AM

Quote:

Originally Posted by 2+2GT

i want to go with a serpentine belt system on my engine, but they only seem to come in a 4 bolt pulley for the serpentine.
Why? It won't make the car run any better.

i just need a 3 bolt crank pulley, alt pulley, and water pump pulley but i cant find em
They are available new from any Mustang vendor, such as Glazier Nolan.

its not for performance. its for the look.

wouldnt you agree, it would look much better with a billet aluminum serpentine setup on there?

and no they arent available from any vendor. i dont want the v-belt. so if you see and SERPENTINE 3 BOLT setup, please let me know.