I have the new 406 in and running pretty darn nice. The pro systems carb is a thing of beauty. Even at 40F in the evening I can hit the key and it starts and idles on its own even without a choke.Very responsive.
What I would like to do is try and get the approx. 300rpm drop out when I put it into gear.
Right now I have initial timing at 14* with 22* mechanical advance for a 36 total. I run vacuum advance and have about 15* of timing added with vacuum.
The 1 issue I have to address is my mechanical is starting to come in at 850 rpm and I have changed springs but it doesn't seem to help.
Am I on the right track to decrease the rpm drop this way. I am considering taking my hei to a shop and have it recurved. I was thinking having them limit the mechanical to about 20* and have it start coming in at 1100 rpm and all in by 2800-3000 rpm.I use 1 of Cranes advance limiter cams on the vacuum advance to limit the amount of timing vacuum adds.

Help appreciated

Jerry

Is your vacuum advance all in at idle?

Jerry, what cam and convertor do you have?

Cam is a lunati 243/251 at .050 solid f.t
Convertor is a 2600. Engine is a 10-1 comp,Edelbrock 200cc e tech heads.

Onavakind - You have me there. I have to assume it is but how do I check?
The engine runs great in my eyes anyway, no bogs or dead spots. I haven't really layed into yet but it definately has a lot of torque compared to my old 350.
Input appreciated

Jerry

I should have added the ditributor is an aftermarket hei Proform, and have about 12" vacuum at idle. I have it iding now at 900 rpm. If any other info need please ask

Jerry

You're never going to completely eliminate the RPM drop while in gear since you only drive the pump in neutral but you work the converter circuits (hope the analogy is correct) once you put in in a drive gear. I suppose you could put a stiffer spring on the dist so timing doesn't add until say 1500, then recurve for 16 initial but same total as now, may help a slight amount. If it idles fine once warm in gear, even if only 600 RPM, then no worries. Don't forget to check manifold vac at idle in gear and choose a PV 1 to 1.5 in hg lower.
Have fun!

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Thanks Doug, With my idle at 950 in neutral and when I put it in gear it drops to about 650. At 650 the engine is how can I say "borderline" I suppose I could bump the neutral idle up a bit more because if I can get it to about 750 in gear its ok. Make semse?? lol
Thanks

Jerry

Sounds like you need more stall

<font face="Arial,Verdana" size="2">Originally posted by JBE:
Cam is a lunati 243/251 at .050 solid f.t
Convertor is a 2600. Engine is a 10-1 comp,Edelbrock 200cc e tech heads.

Onavakind - You have me there. I have to assume it is but how do I check?
The engine runs great in my eyes anyway, no bogs or dead spots. I haven't really layed into yet but it definately has a lot of torque compared to my old 350.
Input appreciated

Jerry </font>


If you have 12" of vacuum at idle, put a mity-vac on your vacuum advance can and see if it is pulled all the way out at 12" vac.