Need new harmonic balancer for supercharged 302

They're confusing crank for crank pulley. Buy the balancer you can afford, powerbond, romac whatever, upgrade to the to the 1 piece vortech pulley, 8 rib set up. 6.87 should do fine for what you're after.

FWIW I used my stock balancer for years with a 8 rib Si with no problems.

Reduces the lag for boost? If you want more psi sooner, pulley down or switch to something other than a centrifugal aka turbo or tvs style blower.

How much boost are you wanting? 3.33 and 6.87 won't have any slip. Search here and you'll likely find different pulley configurations and the psi they made.

Keep in mind boost is simply a measurement of resistance.

Your car is a stock 86 with a cobra intake correct? I made 13 lbs @ 61xx rpm on a bone stock 91 with h pipe and catback using 3.33 and 6.87 on a v3 si with heritage gears and upr power pipe(lower step up ratio than the standard helical gears). You could use the standard 8 rib ratios (3.33 and 6.87)and probably come close to 12lbs with a powerpipe but you probably should have a 3.12 available just in case. Sci vortech right?

Dwain explained the 8 inch pulley deal perfectly.

10 rib is doable but it's over kill big time and TIGHT. Search youtube for channel BREW2L he had a good video showing a ti with renegade brackets using 10 rib. Imo 10 rib isn't worth it for anything stock block. More money, more clearance problems, pita to change the belt.

Fast4Eye said:

Alright so sounds like you basically have the same setup. I have a Sci it with heritage gears also, anderson power bypass and yes a tubular GT40 which is basically a cobra. If I'm going to see 13#s or close to it, then that's enough for me.

Not looking to break more parts than I really need to. So I think I'll stick to the 6.87with a 3.33. Is it worth using the overdriven crank 6.87?

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You have a Sci with heritage gears?

Why would you want to overdrive the crank?

96pushrod said:

Larger crank pulley also allows smaller head unit pulley, which is beneficial on a ribbed setup.

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Right, which would be a 8 inch not a 6.87.

He said

Fast4Eye said:

So I think I'll stick to the 6.87with a 3.33. Is it worth using the overdriven crank 6.87?

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Maybe I'm missing something but a 6.87 is offered in 2 different crank pulley diameters, 6" and 4.75".