I currently have a stock VIII MR with a Walbro Fuel Pump. I am doing full-bolts and Kelford 272 cams. I am shooting for no less than 350whp! Will the stock injectors hold me back?

 

Yes

 

I maxed my stock injectors out (119.5% IDC in EvoScan) @ 315whp on a DynoDynamics. What type of dyno do you want 350 on? Should be possible on a DynoJet.

 

yep Dynojet. I prefer dynojets because the numbers don't vary....

 

Yes, your stock injectors will eventually hold you back. They might get you close to your goal, but if there is ever a problem with a overboost situation or you run the car at WOT at cooler than tuned ambient air temps, you run the serious risk of running lean.

Just replace them, retune and be done with it. They are very simple to install. If you can't tune, your tuner should be able to get you going fairly easily.