Magnum Powers 15% Jackshaft Pulley (custom made)

supercatxr7

Registered User
Charles at Magnum Powers made me this a few years ago. We were shooting for a 20% jackshaft pulley, but I believe this ended up at 15%. He only made 3 of these. Due to the larger size of the pulley the actual jackshaft bracket had to be modified as well by welding up the original tensioner bolt hole on the jackshaft bracket and moving it down to accomodate the jackshaft pulley. I am including the modified jackshaft bracket as well as shown in pic. This larger pulley helps prevent belt slip and increased overdrive without having to move to a very small blower pulley which tends to slip.

sold...



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js pulley

hi, with your js pulley bracket will I need to modify anything on my stock 90 sc or should it just bolt on; direct swap from stock...I am looking for a direct bolt on mod & would not be able to custom fit anything if I run into clearance problems...is the js pulley steel or aluminum? appreciate your time
 
Yes, rib count would be important to know, I'm assuming its the same as any other SC but is a Different belt needed for the larger diameter pully?

Thank you
 
Is the rib just on the jackshaft 8 rib or is the pulley to the supercharger a 10 rib?? Where is michigan are you located?
 
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he's only selling a custom jackshaft pulley w/ the custom bracket to use it with. No sc pulley. He's saying instead of having to overdrive the sc (using a smaller pulley to do so) he had this custom pulley made for more overdrive on the jackshaft. using a smaller sc pulley can result in belt slippage. pulley is an 8 rib. forgot where in Mi he's at but maybe his members page has it. using my cell phone so not as easy to browse.
 
Look I know that it does not come with a sc pulley. Magnums the belt to the crank from the jack is an 8 rib and the pulley on the back to the sc is a 10 and was just checking if it was the same. I was asking about MI since I see he listed michigan as a location and being in mi i would ask about picking it up.
 
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you can use regular crank pulley or the mp 10 percent od pulley. u can use and 8 rib pulley effectively. the mp 10 rib sc pulleys can be used but u'd have to cut the belt to 8 to use w/ this pulley or use an 8 rib belt. believe this was made b4 mp came out w/ the 10 rib pulley kits.
 
OK... this thread has officially confused me...

If I buy this, can I just bolt it on and be good to go or do I need to buy a different belt? I have been looking for a 5% pulley to add to my 10% SC pulley but this would work just as well (probably better actually) and is about the same price anyways so...
 
OK... this thread has officially confused me...
If I buy this, can I just bolt it on and be good to go or do I need to buy a different belt?

Almost certainly you will need a new belt. One of the pulleys on the jackshaft are larger, one of them is smaller. Netting to the gain at the pulley going to the blower. I don't know that I've ever changed to any overdrive pulley system and not had to change belts.
 
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