HEI Upgrade for '78 305

Flack · July 20, 2012

Hi Guys,

I hope I have an easy one for you.

I have a '78 Caravelle boat with a CSB 305 (stock) and I am trying to upgrade the distributor to an HEI.

I took a trip to the junkyard today and picked up a HEI from a '85 Jimmy (350). Turns out though that the unit has a additional harness for an ECM connection while my boat does not have any computers .

So my questions are: 1. Can/should I remove the parts the extra harness goes to, or will it work fine without connecting to anything?

2. If not, what yr(s)/make/model/size would/could I find the proper (2 wire) HEI on?

TIA for your help on this build.

Jason

00Silverado4x4 · July 20, 2012

Question 1: Sorry can't help you.

Question 2:

Just look for and older system that predates the 80's technology. '73-'79(ish) GM Full size truck or car should be able to get you what you need.

Mikeb52r · July 20, 2012

I pulled an HEI distributer out of a '74 Monte Carlo for my '67 pickup. I had a friend install it after I cleaned it up. Don't really remember any additional wires to hook up like a ECM. That was about 18 years ago, but the truck ran a heck of a lot better after I did that mod!