I just bought a used Bigs Stage 5 950HP for my 408. What jeting are you guys running? Idle air bleeds?
Should I go ahead and drill the throttle blades before I install it? The 408 is in the 525-550 hp range.

The carb only has a few runs on it and currently has 76/83 jets in it with no power valve in the secondaries.

Thanks, Justin

I have mine jetted 80 frt and 86 rear. I do have a PV in the frt and the rear is plugged. I have also ran one a friend owns. It was jetted 84 square and had no PV's. Jim

Mine is jetted 81 front 80 rear, no power valves. No idea on idle air bleeds, but car has great idle characteristics.

I have 78 square and both have power valves. It is a stock 950 hp. We drilled out the air bleeds a little bit but I remember something to do with 37s??? Craig

I have a bigs 950, real close to you on HP. no rear p valve similar jetting. my opinion is dont mess with it or drill holes in it. Mine Idles great, works great. right out of the box. clean it up and give it a try. then give Jesse a call if you feel its not doing something right.

Its hard to say without knowing your whole combo, but I would guess your IAB's will be in the .072 range with your MAB's .036. You should be fine with this.

I would mess with your initial timing before you drill the throttle blades. Make sure you get the primary t-slot square first.

Thanks for the replies guys . The guy I bought it from apparently had a rich problem as the front idle bleeds were huge. It had 70s in the rear so I put 71s in the front, it's what I had. I changed the jets to 78 in primary and 84 in the secondary, adjusted the idle screw to where it had about .040" of the transfer slot exposed in the front and about .020" in the rear. The idle mixture screws were adjusted 1 1/2 turns out. I primed it with the electric pump and checked the float levels, the secondary was good but the primary was way high, so it was adjusted down. It fired right up after a couple pumps and idled nice and clean, something I could never get the 750 to do. Tomorrow it goes on a 40 mile round trip and then Saturday it's first trip to the strip. It hasn't been on the strip since October of last year so I feel like a kid at Christmas eve waithing on Santa Claus.

im at 84 squared, on the dyno the motor liked 87 best but that was with forced cold air, no pv's in front or back, fwiw