What spark plugs and cables would you recommend for a 350 engine 1971 cutlass with HEI?

 

R46S AC Delco, is what it calls for, but I think those are getting hard to find, so I'd run a R45S instead. Wires should be a quality 8mm, I use Taylor Spiro Pro.

 

How can it call for that when HEI didn't start until 74?

 

MSD cut to fit wires, they are very good quality and come with a real nice tool for making them up. Spark plugs, just go to the parts store and get what they have, I always use Auto lights in my Olds.

 

The HEI changes the spark plug wires that would have been on the 1971 with points doesn't it? Can I still use the r46s plugs?

 

Do I need to buy plug wires for a 1974 cutlass 350 even though I have a 1971? I am confused.

 

Yes, and Yes.

 

As oldcutlass posted above, you need 8mm wires with HEI style terminals as instead of the 7mm wires with points style terminals.

You can use the same spark plugs called out for the points distributor. I like to gap them just a bit wider (.045") to take advantage of the higher spark voltage, but that is not mandatory.

 

Because he installed a later model Hei distributor.


X2 on what Kenneth said above. Also like I said earlier the R46's may be hard to find, so you may need to go with the R45's.

 

When switching to HEI I've always used the same spark plugs originally called for use with the points, but opened up the gap to .050 or whatever was specified for a similar engine that originally had HEI.
As others have stated you'll have to switch to plug wires with the HEI style terminal on the cap end.
Personally I prefer to use a small cap points-type distributor with an electronic conversion like Crane Cams XR-I or petronix, but it is easy to get replacement HEI parts should you ever have a problem. I just don't like the big cap.
Jeff

 

I would never open the gap to .060" or especially .080" that was specified on some engines. Those were specs for low compression engines running lean mixtures with EGR. For a higher compression performance engines it's OK to keep the gap at .035" but you can open it up some for a larger spark, but I would definitely recommend keeping the gap below .050".