[Calvillo72Nova]

Need help!! Fired up my 396 for the 1st time sti open headers, it idles super high rpm and wont lower. It has a holly 750 vaccum secondary manual choke new carb. If I dont choke it it idles lower with an initial fast idle but then shuts off on it's own almost backfiring through the carb. It fires right up and I did turn the timing down and removed the vaccum advance tonthe carb tonsee if that helped the high rpm idle. I have checked for vaccum leaks and have found none. It's a 396 .40 over, edelbrock rpm air gap intake holly 750 vacuum secondary msd ignition running points distributor due to failure on my pertronix distributor. Any suggestions would be helpful. Thanks in advance

 

[bigmac73]

Need to know cam specs and what ur intial timing is now. Most likely u need to incease your timing and then adjust idle screws

 

[AutoGear]

X2 What Mac said. Additionally, I hope even though it idled fast, you ran it long enough to get through the break in process (especially if a flat tappet cam)