Muffler size dilema for 258 spirit

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   Hello everyone, just gotta ask since I've already done a bit of research and was unable to find some solid info. 
My 258 Spirit is in the works for a new exhaust and I am undecided between these two mufflers:
https://www.magnaflow.com/products/11226-performance-muffler-magnaflow-4-x-9-oval-centeroffset-straight-through-performance-muffler
https://www.magnaflow.com/products/12256-performance-muffler-magnaflow-5-x-8-oval-centeroffset-straight-through-performance-muffler

The shorter one being 20" long(body lenght at 14") and the longer one being 24"(body lenght at 20"). Both oval shaped and center/offset straight through type mufflers.

Up until this point I have been running straight piped directly from the header, but as I started driving it even more daily it has become annoying. Would the short one be enough to silence the excesive noise? or should the longer muffler be needed? Or more importantly would the two of them even fit under the car? Because another fact to consider is that I have never seen the car with a muffler hence I have no clue what size of muffler would fit. 
I understand these are performance mufflers so the sound level will in no way be near the oem specs, but I just want it to be low enough to be tolerable and be able to listen to the radio and have a conversation inside.

Thank you!

Edited by Ricardo540 - May/18/2020 at 11:38pm

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Ricardo540 Members Profile Send Private Message Find Members Posts Add to Buddy List AMC Apprentice Joined: Sep/29/2014 Location: Ecuador Status: Offline Points: 35	Post Options Post Reply Quote Ricardo540 Report Post Thanks(0) Quote Reply Topic: Muffler size dilema for 258 spirit Posted: May/18/2020 at 11:34pm
	Hello everyone, just gotta ask since I've already done a bit of research and was unable to find some solid info. My 258 Spirit is in the works for a new exhaust and I am undecided between these two mufflers: https://www.magnaflow.com/products/11226-performance-muffler-magnaflow-4-x-9-oval-centeroffset-straight-through-performance-muffler https://www.magnaflow.com/products/12256-performance-muffler-magnaflow-5-x-8-oval-centeroffset-straight-through-performance-muffler The shorter one being 20" long(body lenght at 14") and the longer one being 24"(body lenght at 20"). Both oval shaped and center/offset straight through type mufflers. Up until this point I have been running straight piped directly from the header, but as I started driving it even more daily it has become annoying. Would the short one be enough to silence the excesive noise? or should the longer muffler be needed? Or more importantly would the two of them even fit under the car? Because another fact to consider is that I have never seen the car with a muffler hence I have no clue what size of muffler would fit. I understand these are performance mufflers so the sound level will in no way be near the oem specs, but I just want it to be low enough to be tolerable and be able to listen to the radio and have a conversation inside. Thank you! Edited by Ricardo540 - May/18/2020 at 11:38pm

purple72Gremlin Members Profile Send Private Message Find Members Posts Add to Buddy List AMC Addicted Charter Member Joined: Jul/01/2007 Location: Illinois Status: Offline Points: 16611	Post Options Post Reply Quote purple72Gremlin Report Post Thanks(0) Quote Reply Posted: May/19/2020 at 4:05am
	Generally the bigger and longer one is quieter. And make sure you run a full tailpipe. Is the cars engine all stock? Maybe put a stock muffler on it. Stock is usually very quiet

Trader Members Profile Send Private Message Find Members Posts Add to Buddy List AMC Addicted Joined: May/15/2018 Location: Ontario Status: Offline Points: 6882	Post Options Post Reply Quote Trader Report Post Thanks(0) Quote Reply Posted: May/19/2020 at 6:44am
	Beware of Magnaflow's lifetime warranty. It does not include sound. I replaced a pair of glass pack last year that the glass matting had completely collapsed on the inside. Basically no muffler at all and the drone was terrible. All because of a cold start and the car flooded once! Never again glass packs for me.

Ricardo540 Members Profile Send Private Message Find Members Posts Add to Buddy List AMC Apprentice Joined: Sep/29/2014 Location: Ecuador Status: Offline Points: 35	Post Options Post Reply Quote Ricardo540 Report Post Thanks(0) Quote Reply Posted: May/19/2020 at 11:39am
	Thanks for the feedback, and no its not...its running a mild cam and a bigger carb apart from the header I already mentioned. Talking about size dimensions what is the biggest that would fit? I don't even know the size of the stock muffler to start with... because I bought the car straight piped.

amcfool1 Members Profile Send Private Message Find Members Posts Add to Buddy List AMC Addicted Joined: Jun/18/2011 Location: roanoke va Status: Offline Points: 1075	Post Options Post Reply Quote amcfool1 Report Post Thanks(1) Quote Reply Posted: May/19/2020 at 6:28pm
	hi, I have a 79 Spirit. The stock type muffler on is about 19 1/2 inches long. So anything close to that should fit. good luck, gz
	george z