Specifc performance using forged documents

if you know it is forged, then tell the judge the same thing, when he files the case. you will have to ask the judge to sent it to forensic lab and then the matter will continue, if it is found to be not forged.

Is it possible that by using money and influence someone can even prove forged signature as genuine one?

There are circumstancial evidence which also proves that doc is fake and after thought e.g the opposite party did not submit this document in case A which was filed ( in June 2013) later than the date of execution of this fake documnt (in Aug 2012) in respect of subject matter and relevant to it. While submitted in another case filed (in Sept 2013). Can he show some alibi for why he did not submit this fake doc in June 2013 case?

Other thing is that there is no thumb impression, no witness signature while in his reply to my notice said that the alleged doc is executed in front of 14 witness. at some place he forgot to replace the name of donor as he copied the doc from some other doc, notary register entry shows 50A and 50B instead of 50 or 51.

Please advise me experts please

Your query is confusing. If the person had filed case for specific performance based on documents,what you alleged is forged, you can initiate perjury proceedings against the fellow in the same court under 340 crpc. Alternatively you can file criminal cases under forgery and fraud case also against the  person concerned,but the onus is on you to prove the charges.

Until and unless it is proved that the documents are forged and fabricated before the court, you have no chance to go for initiating  criminal proceedings against that person hence first challenge his case properly, get the suit dismissed on the basis of your findings then plan to initiate further action as desired.