couple tech questions

[lewtot184]

setup is 440-505 252 @ .50 hyd cam, dual quad 500cfm eddies, clay smith pump and race pumps regulator. currently running 19* initial i think 37* total as i am still using the black MSD bushing.

when starting hot, cranks over normal speed (fast) have to hold pedal flat to floor for about 10 secs before it starts, wont start at all with no pedal. it runs the same in all weather conditions that i can notice

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any lower initial timing and it runs bad

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i could probably increase but then need custom distributor bushings made to keep total down

I've been playing with a ch28 with dual 600 eddies on the 440 in my '65 coronet (edelbrock heads, engle solid cam, icon 836 pistons). I've got the thing where it drives and starts great. what I found on my carbs was that the idle circuts were too lean and the main metering to rich. basically the calibration was all screwed up. I ended up opening the idle jets up to .0395 (this fixed the low speed surges and roughness), stepped the main metering on the primary side down to .0965 jets with .070x.047 metering rods, use .092 secondary jets (haven't worked with secondaries much yet), and use .110 needle and seats. I have noticed what I believe to be a noticeable imbalance between the upper and lower manifold halves. I do notice a major fuel distribution problem with the 1406 rear carb if it doesn't have the pcv valve hooked up. I was going to write something up for the forums on how I tuned this thing but it's too much work and most people won't heed advice.

 

[coloradodave]

Lew, I for one, love to read intelligent posts (yours are) having to do with tuning experiments. It's all good info to file. I'm sure there are others who would benefit from your experience.

 

[benno440]

I've been playing with a ch28 with dual 600 eddies on the 440 in my '65 coronet (edelbrock heads, engle solid cam, icon 836 pistons). I've got the thing where it drives and starts great. what I found on my carbs was that the idle circuts were too lean and the main metering to rich. basically the calibration was all screwed up. I ended up opening the idle jets up to .0395 (this fixed the low speed surges and roughness), stepped the main metering on the primary side down to .0965 jets with .070x.047 metering rods, use .092 secondary jets (haven't worked with secondaries much yet), and use .110 needle and seats. I have noticed what I believe to be a noticeable imbalance between the upper and lower manifold halves. I do notice a major fuel distribution problem with the 1406 rear carb if it doesn't have the pcv valve hooked up. I was going to write something up for the forums on how I tuned this thing but it's too much work and most people won't heed advice.

I would be extremely interested in your write up please