I tried to bring the timing down today and lean on it some and she didn't like it. Anything below 21* and she feels "bumpy". Bring it back to 23+* and she smooths out.
I had BR7EF's but i changed them out for TR6s. Blower cars like the TR6s, turbo cars like BR7EFs. I had an issue with spark blowout around 6k (this was with the br7ef plugs) i changed them and it fixed the problem. Timing was kept at 21* i think, ill ask Ken to double check