Engine differences?

I have an underpowered M127.984, 135 hp engine in my 1963 220 SEb Model 111. I have the opportunity to buy a 1969 M130.980 or an M130.983 including transmission. The question is will either engine be a slip in replacement without modification for mine? What is the difference between those two fuel injected engines? Is there a difference in transmissions and their connection to my driveline universal as opposed to my 1963 DB4?

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There are a FEW slight differences between the 2 drivelines. However Any one that has the ability to R&R the engines should be able to ADAPT the later engine.