School Me On Distributor Performance
I've seen countless threads where it was advised to recurve the distributor for a notable power increase.
Go back and see how many have actual results.
I purchased a Mr Gasket spring kit. Multiple times I have seen it referenced that you need to replace the heavier/slotted spring with one of the lighter springs from the kit. However, when I got down to the advance weights I found two identical springs, with about 10 loops each.
That was possibly good advice with certain engines, and for drag race only when running points distributors.
Not generally a good shape for a Chrysler smallblock. (see ref 2)
When I played with the timing on the 273, I found that about 34 degrees all in left me about 10 degrees at idle. I'm assuming that leaves me with enough idle advance that I don't need to fool with a limiter plate.
That would be about right for a factory 273. That's
assuming the curve shape and rpms are close to factory
Oh I understand that there are many variables and each engine combination responds differently. I'm not trying to tune to 1/10 of a horsepower. I'm only trying to move closer to a performance curve vs emission curve.
The way to get anywhere with so much hype, so many sales pitches, and so many self proclaimed experts is to understand what the timing needs to do. Then take a look at known working examples. For example comparing the timing on the same engine from the pre-smog to smog (CAP).
ref 1. Here's
a short overview with links back to the Chrysler Tech booklets.
ref. 2. Examples of pre-smog vs. CAP timing in
this post
For a general guidelines on vacuum advance timing - see the How To section here.
How To Limit and Adjust Chrysler Vacuum Advance Cans
For the initial, this will put you in ballpark.
Distributor starting point for a curve
On the engine, move it around to get the lowest rpm it will idle with power. That means going back and forth between the mix screws and the idle speed screw so the transfer slots stay in their operating range. Then adjusting the initial timing a couple degrees to see if you can improve the power or idle speed as needed.