1980 510 single plug Z20 with dual plug head

[Denhamt1983]

I recently acquired a 1980 510 wagon from a family member, but need some advice on getting it running again. The radiator went out while driving on the interstate a few years ago, causing a serious overheat and warping the original head. The previous owner couldn't find a single spark plug Z20 head to replace it with, so he used a dual plug Z20 head under the advice that that all he needed to complete the conversion would be a dual plug distributor. I know it will also need a second coil and the related wiring fabbed up, but is there anything else I don't know about that's needed to complete the retrofit? Also, would I just be better off leaving the original single spark ignition intact and just running one bank of spark plugs? Thanks in advance, really want this survivor back on the road!

[datzenmike]

Just fill the exhaust side holes with old plugs that are along for the ride. Later, if you get a deal on the later dual plug distributor and find a second coil connect it up. The new timing will be around 5 degrees BTDC because the dual ignition points drastically shortens the burn time, the spark needs to be later.

[Denhamt1983]

Sweet, thank you! The previous owner had basically done all you described, just never got to attempt to crank it up like that due to a massive stroke cutting his tinkering days short 😔 good to know it will run with just one bank, tho, drastically cuts down on initial expenses getting her back on the road 😎 my wife's grandfather was the original owner, and it's gonna be her daily driver. One more question, is 5° BTDC going to be the timing with just one bank, or is that just if I add the second bank in? I believe stock timing is 9° BTDC, right?

[datzenmike]

1 hour ago, datzenmike said:

The new timing will be around 5 degrees BTDC because the dual ignition points drastically shortens the burn time, the spark needs to be later.

 

9 degrees for single plug sounds about right.