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I just read trough the entire topic. Looks like something that I really need! I Have a P-1SC-1, 6 rib with factory GM balancer. What would I need to make this work in a 6 rib? 2,5" standoff? what pulley, belt (going to get 3.2" or 3.0 SC pulley) I didn't see specs for 6 rib. I may be blind also...
Trying to get some boost with 6 rib kit and move on to 8 rib when I have some loose change
Thanks for the great thread Chevychad. I might have overlooked it but does anyone know if this mod will work with an 8rib, 7.65" crank pulley and a 4.50" head unit pulley? I realize fir the boost level this combo would produce the standard j bracket may not slip. It's just I have may have an opportunity to purchase a used j bracket that already has this mod performed and I was wondering if the blower pulley would come in contact with the extra idler pulley. And I do not know which size idler the owner of the j bracket used. If that makes a difference I'll have to find out which idler he has on the bracket.
Thanks for the help,
Jason
got my standoff for my 6 rib , where do i get a 2.5 idler ? i need one tomorrow or sat since the car has to be back together Sunday night . advanceauto have them . Also how do i tell what size procharger pulley im running ? i have the procharger off and didn't see any numbers on it .
I made a very small run of ten , just because, it would cost me 850$ to make one, made from 7076 T-6 Aluminum. My plate is now at the machine shop, I am making a notch were the bolt goes, so I can fit a wrench head on it. So I can run all bolts for the blower... This stud is only for 8 rib set ups.. Cool huh...
I just got my plate back from the machine shop, it worked, I put a notch in my plate, to slide in a 10 mm, 1.5 pitch 15 mm head hex nut in, with a stud in the stand off. I am able to fit a wrench in. This lets me be able to run all bolts to secure the blower. I will take pics soon, it cost 50 bucks to machine the plate. Also, I needed to notch it out, to make room for a 5 inch pulley. There was interference, with that size pulley. I am running the large 8.65 harmonic pulley, and wanted to go with the largest blower pulley. I have an F1-A, at 6700 Rpm, the blower will be near 60K.. I dont know how much boost it will make, but I think on my 383, it will be enough. I just wanted no slip, and I know it wont now. Problem solved!!!
Ok, here is my plate, I got it back from the machine shop, they did an awesome job, but the notch was still not big enough, instead of me bringing it back, I took a grinder to it to open it up. I could not wait weeks again. I used a 10x48 stud, from ace hardware, and a flange 10 mm nut, with a 15 mm head. I have no problem getting a wrench in. So what has to be done, is you screw the stand offs on the car first, then you bring the plate up to them, and screw the flange nut on the stud.
This solves the bolt issue. I just did not like the fact, I only could run 4 bolts. I will post pics, when I have it on the car. I will still need to order a belt. This belt is not long enough I do not think. The machine job on the plate was 50 dollars, and not just for the notch, I had to make clearance for the 5 inch pulley.
The system is finally mounted!! So awesome no more slip for me. So, I measured the size of the belt I needed, which was 46.25, gates has a green stripe belt, that is 46.5, part number k080465. That worked out perfect for me!!
This is for the 5 inch pulley, and for an 8.65 harmonic pulley. You want the tightest belt fit possible. It was hard to install, but it went on. That way, over time when the belt loosens there will never be interference.
As a thought, If your running a stock ls1 with around 8 or 10 lbs, you dont really need to machine your plate like I did. However, I will have high rear wheel hp, and wanted to run all the blower bolts, and I am glad, I found a way to do that. I have 9 of these parts left. After that, no more, because they are very expensive to machine, when small runs are made.
I am looking into this mod for my P1sc setup since belt slip is an issue. I was wondering if someone would be kind enough to share what belt length I would need.
6.0/3.0/2.5/2.5 = ?? belt
6.0/3.0/2.5/3.0 = ?? belt
There are some other modifications I suggest you make if you install the fixed idler pulley. I suggest you tap another hole in the Procharger J Bracket. The extra hole allows you to secure the J bracket to the alternator bracket since you loose one 3/8 bolt which is hidden under the pulley after mounting the pulley on the J bracket.
As a result no way to tighten the bolt. See pics in link.
Pic of J bracket with extra bolt hole drilled so an extra bolt can be used to secure the J bracket. You will have to ask Procharger why the J bracket does 'not' come with this hole drilled. Or maybe it does - I have a 2005 version of the J Bracket.
Note: You can purchase a smaller 50 MM idler pulley. The 50 mm idler pulley allows you to insert a bolt to secure the J bracket because the pulley is smaller. PM me for the source. It is off a Cadillac with FI.
Last edited by dlandsvZ28; Dec 27, 2019 at 08:00 AM.
Reason: edit content
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Glad to see this mod still alive after all these years. 
