Garya - 7:31 pm on Jun 24, 2013 (gmt 0)
It might not be the spammy links in the 301.
The only way to tell is to undo the 301
and see what happens to the old re-directed domain.
I had the same problem I had and old domain with 1000 of old spammy links that re-directed to my main domain, after my site was hit in penguin 2.0 I removed the re-direct.
My old domain with all the spammy links is ranking all over 1st and 2nd page. I thinks that google spammy links is just a farce.
I see 2 of my competitor have 70% of there links spammy. Their is more to it then that. I think its just the opposite, to many good links that are
dubious will trip the algorithm or 2 many good links from the same c-class will do it also.