performance curve distributor

-
63dartman

63dartman

Well-Known Member
Joined
Dec 11, 2005
Messages
2,230
Reaction score
24
Location
rio rancho, nm
Is it worth the extra money for a aftermarket distributor with a "built in performance curve"? I understand that the distributor is just a trigger for the spark but, I can't help wondering if my autozone vacuum advance distributor is not up to par for my msd box and high energy coil.
Also, what are the issues going from vacuum to mechanical advance? I want to get the best performance with good street manners. I've been looking at the mechanical msd billet for around 200$. Would this be a worthwhile upgrade or am I just throwing away money?
 
The MSD is nice but you could recurve your distributor for cheap.
 
The aftermarket distributors were made to be easy to modify the advance curves. Your factory ones weren't. With an aftermarket you could try different things easily and find what works best. A lot work with a factory distributor. If you knew what you needed, as far as how fast it comes in and how much mechanical advance is in the distributor, a couple of hours on a distributor machine would be all you need. Now as far as vacuum versus mechanical advance, if its a street car, use the vacuum advance. If you just use mechanical advance, you'll see your gas milage go down a lot (20%?).

don
 
easy to recurve...all you need is a welder and file to shorten up the slots for the mechanical advance and lighter springs....
I even have a page right from Mopar in the 70s with 2 cartoon characters...it says remove the heavy spring and stretch the light one...May come in too quick doing this though...I used 2 light springs in mine...its a trial and errror unless you have access to a dist machine, but definately doable at home on a stock distributor
 
Yep I have a stock electronic dist in my boys Dart. I changed the springs and recurved it to get full advance by 1800 rpm. Works good on the street with no ping and great performance. You can weld the slots on some to limit mech advance and add initial or whatever as like was said alot of times you have to try different setups. I picked up a Mallory dist cheap for my 63 and it is nice that the good performance dist has many adjustments so you dont have to weld or anything on it. And I dont use any vacum advance as you dont need or want it when you use a very fast mech advance. I never checked the gas milage but I dont build my muscle cars to get good gas milage anyway. I just build them for the best performance with what I have in them. Ron
 
depending on how radical a build is, you may see very little change in fuel economy without vacuum.

Vacuum advance sure comes up for debate a lot.
BUT that is a different topic...

Curve can make a big difference.

This year I shortened my curve to 12 degrees (was 16). Bumped initial from 20 to 24. Picked up 2 tenths. It surprised the heck out of me.
 
Yep, I am not worried about gas mileage, I want the best performance, and I still want descent street manners. Now about this home recurving......How do I do it right? I don't have a distributor machine, I do have a descent timing light though. Is there any site that gives any tech info on recurving? Should I just recurve my cheepo autozone vacuum advance or go for the msd mechanical and start with that?
 
I just welded the slots shorter by 1/8" and filed until square, and swapped the heavy spring for a light one from another distributor
total timing in by 3200 rpm, set to 32-34* at that rpm
done!
 
You neeed a tiing light with adjustable advance ability, or a balancer marked to about 50°, or your balancer with a timing tape. If you use your own, I would verify TDC first, then attach a balancer tape to it. You need to see timing marks at full advance. Some timing lights have an adjustment to "dial up or down" the flash of the light so as you dial in ° of change, the flash still occurs when the mark is at the "0" position. For the cost of about $50, you can have perfomance equal to any MP, Summit, or FBO factory based distributor hi-po ciurved distributor. Quality wise, the MSD Pro billet or MP billet is a better material, better bearings, less parasitic drag, etc..But really, how much are you giving up for that extra $200?
 
Thanks Moper and all, I went out and got a timing tape from my local mopar guy(six pack performance). My timing light doesn't offset the degrees but the tape goes up to 60-70 degrees. I will probably cough up the money for the msd just for the mechanical advance. It will probably be a couple weeks before I get to it though. I have some honey do projects that need to get done. Gotta keep the peace!
 
Not sure if Mallory makes both, the small and big block kits
for Mopar. I know that they make the kit for the small bock
for sure.

I found three kits on mid 80's Furys where they changed them
from the lean burn system. I paid 40.00 for 1 whole kit and 2
spare dist's.

They are easy to dial back the total advance so you can have
more initial advance.

Dann
 
You must log in or register to reply here.
-

Back
Top