Howdy,

I'm running a Magnum 380hp crate with a Demon 650 double pumper and was having lots of problems fouling out plugs and running very rich. I changed the primary jets from 70's to 67's and the car ran much better but still fouled out the plugs. After some research and a vacuum test I found that the power valve (6.5) was much to large for the amount of vacuum I was pulling at idle. It has a pretty healthy cam and only pulling 8hg in drive and warm. I was told to put a rating around half that of the reading on the gage so I put a (3.5) in. Because I thought I found the problem, I placed 69 jets back in the primary for fear of being to lean. Well... I took it for a ride and I'm still running to rich and now sending raw unburned fuel through the tail pipe! So... Here's my question. Should I put the 67 jets back in and hope for the best or tweak my timing? My timing was dead on with the 67's and larger powervalve and it should still be dead on. Not sure why it would change? When you ease into the gas it run's fine, but when you give a little more throttle, it spits, farts, and act's like it's getting a ton of fuel.

Any help is appreaciated!