Just stuck a blue V8 dizzy into the red 308 in my HZ tonner. In the process discovered a little trick. When attempting this, throw away the big, expensive standard 2-piece dizzy cap and rotor button. All you need to do is leave the original dizzy cap and leads on the engine as it fits the electronic dizzy. All you need is an XD/XE Ford Cleveland rotor button. Simple as that. The only other bit you need is an extra spark plug lead as the tip of an electronic dizzy 12V coil looks like a spark plug and the red motor coil lead doesn't fit. And of course you need to bypass the in-harness resistance for the coil supply. The problem I found with using the bigger dizzy cap is it fouls on the manifold vacuum brass attachment, and you can't get much adjustment on the distributor as a result.

I always wondered why they used the big cap. The small size cap was used on the 6-cylinder engines and wasn't a problem on other V8's eg Cleveland. I thought it might have been a cosmetic thing, or even a carry over from the Chev HEI style dizzy with the

Must be some truth in what Paul and Byron are saying....my 5 litre VN engine, and the VR HSV GTS 5.7 litre V8 we have at work, also have small cap distributors. There's no room for a large cap distributor in a fuel injected V8 anyway!
I'm sure GMH would