I am rebuilding two FL 350 engines. After taking then apart I found that both of the engines have Two base gaskets one with nipples (stock) and one with out nipples. The one with out nipples looks the same as the other except it flat.

Any one know what this is all about?

Sounds like someone didn't realize the gasket was there or was just too lazy to remove it. Maybe he though he could keep the oil out of the starter by doing this.

Rand

I guess that's possible. The engines came for two different places. It looks like they were worked on by different people, one of the engines had a lot of Yamabond on the gaskets and the other didn't have any on it at all.

So I asked around here and the thought is that the previous owner's were trying to get more top end by change the port timing. Dose that make sense?

One I just took the top end off had two gaskets

2 gaskets will lower compression. Port timming wont change much by the thickness of one gasket.