Person who posted about the lemon law in Mass?? .... Here's what it says about Massachusetts Lemon Law. The key words here are "and can prove"....
The Used Vehicle Warranty Law requires private party sellers to inform buyers about any and all known defects which impair the safety or substantially impair the use of the vehicle. The law applies to all private party sales regardless of sales price or mileage. If the buyer discover a defect that impairs the vehicle’s safety or substantially impairs the use, and can prove that the seller knew about the defect but failed to disclose it, the buyer may cancel the sale within thirty days of purchase. The seller must refund the amount the buyer paid for the vehicle, less 15 cents per mile of use.
Obviously, this doesn't apply to California unless their laws are similar.
However, I can tell you that if the "gasket" you put on the engine was a head gasket, it should have been pretty obvious the first time you drove it if that's what the engine needed since it would have nearly overheated (if not actually overheated). How much mileage was on this? The repair shop should have (hopefully) given you some sort of warranty on their workmanship, regardless of what they did. If this was a head gasket and you can prove the workmanship was shoddy, you may have a shot at the repairman or the shop to sue there instead.