dc_sniper9130

Here's what I'm gonna be running:

270/270 470/470 hyd flat tappet cam

1.6 Rocker Arms

305 bored .030 over

I picked up an older mechanical q-jet at a swap meet for like $25, planning on rebuilding it ($35). I know SBCs will run just fine with one because thats what they came with, but if i'm going to be pushing 325 horsepower, do I need to put bigger jets in?

Thanks

xpndbl3

iTrader: (5)

I doubt that motor will be putting out 325 horsepower, but good luck. Jetting will be determined when you get the motor running and pull plugs.

dc_sniper9130

well I only put the parts in there pertinent to how much fuel/air would actually be going into the cylinders, the only stock parts on this motor are really the connecting rods...

but thanks for the info. what exactly would I be looking for? wet plugs, fouled, etc?

xpndbl3

iTrader: (5)

google plug reading and check out the pictures, or holley tuning and look at the plug pictures

dc_sniper9130

Sweet, thanks man.

Damon

What jets are in there stock?

72s are very common. On a hotted-up 350 or larger motor a bump of 4 jet sizes over stock on the primary side is often a reasonable starting point vs. the stock "emissions" calibration.

Often the idle circuits will be too lean as well with a wilder cam. That's easy to fix, too, but changes are irreversible so you must be careful and go in small increments. I'm NOT talking about jsut adjusting the idle mixture screws here.

dc_sniper9130

I have no idea. I just yesterday looked up the serial. It's from 1976 and off a Chevy originally, and California-Emissions legal (not sure if that's good or bad).

Mine's a hotted-up 305 though, would that four-jet jump still be advisable?

Damon

Depends on the starting point as much as anything. Certainly you can't hardly every go far wrong going up at least 2, assuming the jetting in it is stock right now.