mooncows said:K so i might have found the problem but not sure. My new carb has 2 vacuum ports, and originally the dist vacuum was in the drivers side but ive read its supposed to go on the passanger port. Could this affect my performance?
No. You'd have to check which is which but usually you'll have at least one port that is full manifold vacuum and another that is timed vacuum.
Obviously full manifold vacuum means you have your highest vacuum at low throttle application and close to zero at full throttle.
However timed or ported vacuum is the exact opposite. You have zero vacuum at low throttle application and more vacuum at full throttle.
I know its been debated over and over on which is better. Personally I've tried them both and didn't notice much if any difference between the two.
You can experiment with it but it's not going to really gain you what you think it is.
Just remember power is in the heads. If the heads don't flow well, then whatever you bolt onto the engine isn't going to do as much as it could.
And as mentioned before, what were the weather conditions like between your best run and these new runs with the aftermarket stuff added? As in was it colder out with the better run?
You'll likely find out that the 305 is similar to the Olds 307 in terms of performance. Your not really going to see a whole of gain just by bolting on a few external items. You'll have to dig into it (heads, cam, etc.) before you'll really start to gain anything.
What distributor are you using? I'm assuming its an older vacuum advance HEI or some aftermarket piece? If its the stock CCC-HEI distributor then that's likely part of your problem.