Port matched cases

[CAJUN BANSHEE]

I mentioned this in my other thread but didn't get a response. So what is so special about port matching cases for a specific top end? for instance, I had a 421 cub built and upon assembly found that the cases were damaged. I started looking for another set and found one already port matched for a cub. But people are telling me not to do it because it was not matched to my setup. I do understand if the sinario was a large bore motor but this is just a 421 cub. Please give me some input on this so I can make my decision either way. Thanks in advance yall

[gotta_goatsfast]

Basically you add and remove material from the case to provide a better airflow into the transfers. Since the 421 transfers do differ slightly from the openings in the case, you can reshape the case so there is no lip where the case meets the cylinder. Its usually good for 1-3hp.

 

If the other case was port matched to a cub (assuming same cylinder as yours) it should be close enough to run. A 421 cub is a 421 cub, the tolerances don't vary enough (unless someone specifically ported one or the other to alter the shapes) to make those cases useless. I'd say verify what cylinder was ran on those cases. If it was the same cylinder you run, go for it.