HEI with and without separate CDI box?

[67Dad]

Other than price, what are pros/cons/options of using standard GM (or aftermarket clone) HEI distributor vs. separate coil hookup vs. full CDI multispark box. We are NOT looking to race. (1993 350 with vortec heads, moderate cam). Summit? Mallory? MSD? Accel?

Does anyone know if the larger sized standard (larger diameter) HEI will fit or how high it sticks up out of the manifold? (we rebuilt the engine and it didn't have the ignition).

Thanks!

Mark

[truckster]

I have a stock GM HEI in mine. It's a little tight, but it will fit.

As far as advantages, it's extremely dependable and durable, better starting, and installation couldn't be simpler. Just remember you need to run 12v to the HEI coil; don't use the resistor wire from your points ignition.

[bobs409]

And carry a spare module and the tools to install in the glove box. When they go, they don't care where you are at.

[Fitz]

Originally Posted by 67Dad

Other than price, what are pros/cons/options of using standard GM (or aftermarket clone) HEI distributor vs. separate coil hookup vs. full CDI multispark box. We are NOT looking to race. (1993 350 with vortec heads, moderate cam). Summit? Mallory? MSD? Accel?

Does anyone know if the larger sized standard (larger diameter) HEI will fit or how high it sticks up out of the manifold? (we rebuilt the engine and it didn't have the ignition).

Thanks!

Mark

The GM HEI distributor will fit. The module inside is made for GMPP by MSD.

[67Dad]

Any pics or guestimate of clearance between distributor cap and firewall?

[GASoline71]

They fall right in with a lot of clearance from the firewall. Unless you have the motor mounts in the wrong spot during an engine swap.

If you're not racing, or have a high HP engine. Then a stock HEI without any boxes or fancy stuff will be just fine. Just make sure you have a dedicated 12v wire going to the distributor.

I have an MSD Pro Billet HEI... which has all the CD stuff in the module and also has a rev limiter too. All under the cap.

Gary

[67Dad]

Nice! Do you recall which model MSD that is? We probably don't have quite that much room...we used the "old" engine mount locations (original 6 cylinder) which pushes the V8 back and inch or two compared to what the original V8 location was, as we understand it.

[Fitz]

Originally Posted by 67Dad

Any pics or guestimate of clearance between distributor cap and firewall?

Here is a photo of a VERY long big block running the GMPP HEI dizzy. There is about two inches between the Distributor cap and the firewall. If this fits I know yours will:

[67Dad]

Wow...that is a spectacular setup! Congratulations.

With the old/wrong mounting for our V8, we don't have this much room. The "stock" distributor (that we found in a box of parts...EFI style...5" diameter, 7" tall) fits, but without much extra room. The "replacement" MSD styles except one are about the same diameter but are taller...which makes them questionable but possible...a local OReillys will have one in the morning we can try. We found one other MSD one that is adjustable and smaller, but of course that one would require an extra $200 for the ignition box. It's always something!

Thanks to all.

Mark

[CSGAS]

When you put that 93 engine together, did you re-use a factory hydraulic roller cam? If so, you'll want to get a melonized gear to install on the distributor you do finally use--no matter what variant ends up fitting to your satisfaction. If it's using a hydraulic flat tappet instead, you won't have to change anything.