have a 1979 monte carlo with a 305-has a spreadbore edelbrock intake-a carter afb 600cfm electric choke carb-stock hei with the lightest advance springs-


my question is this-i have read that all gm hei's have 20degrees of machanical timing built into them-but i ran the numbers on the stock distributor,and found this

distributor #1103282
0degrees @1000rpm
10degrees@1700rpm
20degrees@3800rpm
it is factory set at 4degrees BTDC

stock vaccum can has 0degrees@4
20degrees@10

are the canister #'s refering to timing degees at crankshaft or engine vaccum


i am confused because most of the info i have read on timing says that to calculate total machanical timing, you take degrees at crankshaft which would be 4degrees BTDC + 20degrees of machanical advance from distributor-using this my 305 would only have 24degrees of total machanical advance- I would like to have about 32-36degees total machanical-or is this too much timing for a stock 305