mid range rpm misfire

[ddettloff]

68 318 with all new plug wires, plugs,and cap eldebrock carb headers.
car idles great timing set 5 degres before tdc has vacum advance dist.
during accleration under load it starts to mis fire at about 2500 to 3000 rpm.
have the carb fuel mix screws turned out about 2 full turns any ideas.:banghead:

 

[Mrmopartech]

Set the timing to 12-15 degrees before TDC and reset carb and try it,mrmopartech

 

[OldmanRick]

I agree with "mmt". A stock 318 can use way more timing. Curious to how old/miles are on this engine?

 

[ddettloff]

motor just rebulit approx 2500 miles on it live in denver car runs at attlitude of 6000 ft will this efffect timing

 

[Bulldozer]

i have a 67 318 , just about the same identical set-up as you with a 1406. my timing is at 32* @ 2500 rpm total advance , and with the HEI ignition , it runs like a raped ape. im just south of you in the springs

 

[OldmanRick]

Assuming you are running a electronic dist. you may have a grounding issue with the box? Other members know much more about this then me. Hope they will chime in on this.

 

[green1]

Adjusting the idle screws has nothing to do with the problem; fine tune the ignition first.

 

[66dartman]

if you can, put a timing light on it, watch the timing marks,& rev the engine and make sure the advance is working in the distributor. It should go past 30* at 2500 rpm.

 

[midlife89]

Have you tried running it without the vac adv hooked up?I had an issue with vac adv adding too much timing,caused a miss in that rpm range in mine.Have you checked what your timing is with the vac adv connected?Mine was at 60 vac adv connected,limited it's travel with small washers.It solved my miss.Couldn't find any with less pull.