The 2010 endorsements are coming fast and heavy, as Mitt Romney on Thursday announced four more endorsements through his Free and Strong America PAC.

The new endorseees are three Republican incumbents and one GOP challenger in California. Romney will send $2,500 checks to Reps. Brian Bilbray, Mary Bono Mack and Dan Lungren, as well as attorney David Harmer, who recently lost a special election to Rep. John Garamendi (D-Calif.) and is now challenging Rep. Jerry McNerney (D-Calif.).

Lungren and Bono Mack are two of the more vulnerable Republicans on the map. McNerney's seat is one the GOP would like to win back after losing it in 2006.

Romney has also endorsed a series of candidates in both Ohio and Missouri.

Minnesota Gov. Tim Pawlenty announced seven endorsements late Wednesday, and Sarah Palin announced 20 districts she is targeting last week.