Serpentine upgrade? Yes or no?

mrbone · Friday at 10:28 AM

Street 512 going in my 68 roadrunner to replace a mild 383. Considering 440 source alternator, pulley and bracket kit. But, wondering if I should upgrade to a serpentine belt? Currently running a single alternator V-belt- no power steering or air conditioning. Thanks for your input.

Sixpactogo · Friday at 10:54 AM

Serpentine set-up is quieter and prettier. It is only an upgrade if you can find pulleys akin to the factory set-up. I made the mistake of getting an underdrive set-up that saved horsepower but slowed down everything causing issues with overheating, the alternator discharging at idle, etc....That said, if you don't want to deal with those issues, make sure you get the correct pulley sizes. The Factory sized them properly so you don't have to.

j-c-c-62 · Friday at 11:01 AM

With only WP and Alternator, I would not bother.

Frankb · Friday at 11:10 AM

I agree with jcc however you may have issues with alt belt slipping with that 512. A serpentine system would fix that

gkent · Friday at 11:38 AM

I have only ONE thing driven by a belt ... the alternator. I use the 440Source serpentine crank pulley aand the ulley that comes with the alternator (Denso 90 amp). No tensioner. Works great.

I you're interested I also have the 440Source water pump pulley and alternator pulley for sale.

Its worth noting that they no longer show anything other than the w/p pulley on their website !!

mmissile · Friday at 12:50 PM

JMO....but I think billet-serpentine stuff belongs on street rods. If your car is a resto-mod, it'll look at home.

ckessel · Friday at 8:25 PM

I bought the package from SD Concepts many years ago for my 65. Have not used it yet though since the car is on back burner. I like it because of the easy to source accessories and service parts. Straight vane water pump, 94-02 Ram/Dakota/Durango/B van alternator, S10 tensioner, Sanden compressor, 99-05 Jeep p/s pump.

Runcharger · 2025-11-08T08:45:21-0600

Yes: Personal preference. I dislike that Boydish ornamental appearance. I prefer the simple, stock look. I have installed them too and am not crazy about them at all.

gkent · 2025-11-08T09:59:14-0600

If you don't like the billet look, paint them black !! A serpentine bely has WAY more surface contact on the pulleys - virtually no chance of slippage AND less chance of cracking because they're thinner.

Just some points to consider !

Serpentine upgrade? Yes or no?

mrbone

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Sixpactogo

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j-c-c-62

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Frankb

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gkent

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mmissile

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ckessel

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Runcharger

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gkent

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