I need advise on proper timing set up for IH345 with split duration cam & Pertronix

I have to ask this because it has caused many a lot of lost hours chasing a similar idle issue, but did you install the correct intake manifold gaskets? If 266/304 intake gaskets are installed in a 345/392, it will create a huge vacuum leak and act the same. A quick check at the top of the gaskets is a tab showing which engine they fit. Double check you got the correct ones in there just to be sure.
 
Robert Kenney said:
Sounds a lot like a fuel supply problem. You should install a fuel pressure gauge and see what is being supplied to the carburetor. Vacuum leaks are usually not variable, like you are experiencing as it warms up it seems to improve then get real bad.
Another thing is that you could have a large vacuum leak through the PCV circuit as well. Block the carburetor port that supplies vacuum to the PCV valve and start it up, see if it improves.
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Hi Robert, Thanks for the information. I did not get a chance to start the Scout this weekend as I need to get a vacuum port installed on the manifold first before I start it the next time plus I had other things going on. Eventually I did come up with some time to check the intake manifold bolt torque and the carb base torque. Intake manifold torque checked out ok. I did find that when I had to change out the carb studs to accommodate the Lokar throttle and kick-down bracket I had only snugged them tight, that could be my possible vacuum leak if I had one at the base of the carb. The Holley manual calls for them to be torqued down to 60 to 80 inch pounds. I don't have a inch pound torque wrench so I torqued them down to 6.5 lbs. of torque which is the 80" in pound equivalent. I also went to the hardware store to get some fittings to make a 1/4" vacuum port for the intake manifold. This coming up weekend I should be able to test and tune further. Thanks again for your advise.
 
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