Alfie and others..
I have an HEI on a 327. It is a "no brainer" to do. Get an HEI distributor
for almost any Chevrolet between the years of 1974 and 1979. (I'm not positive
of the beginning and end dates.) What you want is the HEI with vacuum advance,
which is BEFORE the cars had computers, and it is cleanest to get the ones with
the coil integrated into the cap. (I know that 1981 had computers. I think
1980 had no vacuum advance). I got mine from a 1977 full sized Chevy wagon.
The differences from one Chevy model to another are basically in the spark
advance. A Motors Manual for that year lists all the distributors by number
and the amount of vacuum advance for each. This might help you select an
appropriate distributor. If you can't find the "perfect" one, you can always
buy a kit with weights to change the curve. Look on the shaft of the advance
module to see the maximum amount of advance the module is capable of. There
will be a stamped number such as "10". That means 10 degrees of advance
maximum. The max is set by the length of the slot in the advance arm.
>From a donor engine, pull the distributon with the advance and the coil. I
>found mine at the local pick-n-pull. Be careful, often people take the
>ignition modules (which is under the cap). You can't use the original coil,
>even if you don't get the integrated coil. They don't have the correct
>characteristics.
You'll also need to do a little wiring change. You should remove the old
distributor, coil, ballast resistor and bypass circuit. Stock, there is a wire
from the START side of the ign switch to the starter. On a separate lug on the
starter, a wire goes to the coil and bypasses the resistor. This wire is the
by-pass circuit....remove it. Don't remove the wire from the START terminal to
the starter or it won't start.
On the RUN side of the ign sw. there is a wire going to the ballast resistor
which then goes to the coil. Remove this wire and the resistor and replace it
with a new 14 gage or (numerically) smaller (physically larger) wire to handle
the current, that goes directly to the distributor cap terminal labled "ign" (I
think).
Keep in mind that because there is nothing to look at (like points) you have
only ther rotor position to determine when a spark will occur (approximately).
If your timing is waaaaay out it will be difficult to even get the car running
enough to set the timing properly. On the other hand, the spark is so hot that
it can be quite a ways off and still run (I hope that makes sense). Be sure
the engine is on #1 TDC for compression before removing the distributor...that
will mitigate significant problems.
Regards,
Jon '53 3100 w/ 327 HEI
-------------------------------------------------------------
Sign up for ICQmail at http://www.icq.com/icqmail/signup.html
oletrucks is devoted to Chevy and GM trucks built between 1941 and 1959
|