Bill, Larry says the whole distributor needs to be replaced to use Pertronix. Are you saying that with my friend's existing unit, all he needs to do if buy a remote coil and a new cap and he can use the distributor he has in there now?
Yes, unless someone else sees a fly in the soup. The HEI distributor is bigger than a points distributor, so you need to test fit the new cap first. It really depends on how much more clearence he needs to get the air cleaner on. Also, I see you using 90 degree spark plug wire connectors off the cap. And make sure you get a remote coil for an HEI. Every engine is a little different depending on where the engine sits, the hood height, etc. I am assuming this is a GS style air cleaner. - Bill
Ken, we need more information. Without knowing exactly the nature of the interference here we have no way of knowing whether the cap Bill suggests will work or not, unless someone's already tried one. Even though the coil features are gone from that cap, the diameter is still larger than the old small body distributor caps and the height may still be an issue without trying one or at least knowing the dimensions. The reason the small body (points-type) distributor has been suggested as a solution with some certainty is that the factory designed the air cleaner assembly with that distributor and cap in mind. Devon
For looks, all he has to do is remove the 'cup' lower portion of the snorkel over the distributor and put it away for safe keeping. 6-8 small bolts holding it on. It should clear the distributor then, and from the top still look ok You'd really have to lean in and look down the foam to see there is no cup. free :laugh:
Bill, I've never seen that cap for a GM HEI. It looks like a cap for the small body distributor with HEI type terminals. The GM HEI cap has 4 hold downs. That cap looks like it only has 2, like a points distributor.
I see what you're saying, I didn't realize an HEI cap would be larger diameter. The nature of his problem is that the front snorkel portion of the stock 72 GS air cleaner assy. was contacting the coil and was not allowing the rest of the air cleaner assy. from going down on the carb all the way. Whether it's diameter or height, that I'm not certain. I just haven't had the chance to stop over his house to check. It might just be easier to buy the one online which is a stock points distributor and buy a pertronix and be done with it. That way I know it would fit.
You are correct - there's that fly! After further digging I find that is for a late model HEI which has a remote coil from the factory. MSD sells an adapter (MSD 8401) which allows a remote coil but does not save any space. Sorry Ken. Plan D - No one has mentioned Dave's small body conversion which may be a more durable option then the Pertronix. I'll go back to my cave now... - Bill
Well, I looked at it last night and this one has 4 hold downs. It has a connector going to the coil which is a white-striped black wire (assuming ground) and a red wire (assuming 12v). Then, from an adjacent connector comes 3 wires, a red, a brown and another (maybe black>) going from that point down through a grommet right into the aluminum body top plate portion of the distributor. I'm thinking this whole distributor, cap, coil, the whole 9 yards needs to be swapped out with a stock sized unit to allow the snorkel to seat, correct?
Awesome thanks Larry! I was looking at this, whatcha think? https://www.napaonline.com/Catalog/CatalogItemDetail.aspx?A=NRD481814_0271587292&An=0
When I put all the GS stuff on my '71 ( intake,carb,hood,air cleaner assembly ) I had the same problem with the HEI I had installed. I fixed it by putting the stock points dist. back in along with a MSD 5 box. This only puts a small amount of voltage through the points as a trigger for the MSD, doesn't wear out the points at all. Starts and drives like it did with the HEI. Ken I think I have a MSD 5 somewhere if you're buddy is interested in trying that route. I might even have a stock dist and could sell him a package deal. I'd have to read back thru the thread but was this a 350 or 455?
Harold I appreciate that. I think that we will probably go with a stock points style distributor and I already have a spare stock coil I am going to give him and he's gonna install a Pertronix in place of the points. I appreciate your offer though. What I would like to know is when we hook up the new stock can-style coil I will have to cut that connector that powers the HEI coil off at the end of the harness and just connect the black and red wires directly to the stock coil correct?
It's probably not going to be that easy. The original wiring for the stock points distributor contained a "resistance wire" which dropped the voltage below +10V, probably around +8V. The HEI was originally designed for a full +12V, most people making that upgrade cut the resistance wire out of the harness and run a standard wire to the HEI. So you'll need to check that wire's voltage to know if it's been modified or not. If so, a resistance wire needs to be spliced back in as it was from the factory, or a ballast resistor will have to be placed in series to drop the voltage back down. Devon
I'm not an expert here and someone will correct me if I'm wrong, but when they converted your buddy's car to HEI they would have bypassed the resistor wire in the stock wiring harness andhooked a full 12 volts to the power wire on the HEI. If you convert back to a stock style points dist. you will need to use the resistor wire to keep from burnig up the points. BUT, I think the Pertronix unit would require a full 12 volts ( check the instructions ), so then you could re-use the power wires that are currently on the HEI. My .02, anyone feel free to chime in and correct me here.
