My 408 seems to like to idle a little high. Around 1000rpm. it drops to around 650 in gear. If I turn it down any more than that it wants to stall in gear??
What displacement is your engine?I just have to figure out the tuning, It seems to want to idle a little high. I set it at 16 deg. initial and it runs great, but when I hook up the vacuum advance the idle soars to over 1000 rpm. I turned the curb idle screw all the way down and can't seem to get the idle down. I have the Pro Systems carb on their, will an engine like mine run at a bit higher idle? Cam specs are: .594 In, .611 Ex., Adv. Dur. 273 In. 279 Ex., [email protected] 221 In. 227 Ex. Lobe sep. 112. Also, what the best way to set the air/fuel mixture screws? Where is a good place to start with them?
You're fine at 14 - 16 deg initial before vacuum kicks in. That's the whole idea of ported vacuum, Depending on the build, every engine has its sweet spot. Mine has always been 14.5 deg initial with zero ported vacuum which hits total of 36 deg advance at 2800 rpm.I think I went about the initial tuning all wrong, I was starting at 16 deg initial before hooking up vacuum, I think I have to start at 6 to 8 deg initial, get it idling, then go from there. I am in the process of re-torquing the heads and re-setting the rockers. I called Pro Systems yesterday and found the inside tube IS ported vacuum, the outside one is manifold vacuum. I will keep everybody posted!!
Disconnect the distributor vacuum hose and never, ever plug it in again.I think I went about the initial tuning all wrong, I was starting at 16 deg initial before hooking up vacuum, I think I have to start at 6 to 8 deg initial, get it idling, then go from there.
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