Muffler help for 65 327 4 barrel

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   Looking to replace the mufflers on my 65 327. From the research I have been doing, it looks like 2.5" is the biggest pipe I can run without negatively effecting performance. What would be good mufflers to run? Was thinking super 40, wasn't sure how a glass pack style muffler would preform on the car. What do you all recommend? Thanks 

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mark_k Members Profile Send Private Message Find Members Posts Add to Buddy List AMC Apprentice Joined: Jul/30/2020 Location: Kentucky Status: Offline Points: 214	Post Options Post Reply Quote mark_k Report Post Thanks(0) Quote Reply Topic: Muffler help for 65 327 4 barrel Posted: May/25/2022 at 1:59pm
	Looking to replace the mufflers on my 65 327. From the research I have been doing, it looks like 2.5" is the biggest pipe I can run without negatively effecting performance. What would be good mufflers to run? Was thinking super 40, wasn't sure how a glass pack style muffler would preform on the car. What do you all recommend? Thanks

Trader Members Profile Send Private Message Find Members Posts Add to Buddy List AMC Addicted Joined: May/15/2018 Location: Ontario Status: Offline Points: 6913	Post Options Post Reply Quote Trader Report Post Thanks(0) Quote Reply Posted: May/25/2022 at 6:47pm
	Don't know what case size your looking at, but personal experience with glass packs has been poor. One on a Jeep, the engine flooded and the glass packing collapsed in the muffler when it finally started. The other engine was running rich and the glass just packed full of carbon. Pretty much recommend turbo type mufflers now. Just have to decide on size you can fit, noise level, material quality and budget. Best to find a vehicle like your own or close to it, find the sound you like and let that be your guide. Everyone will have their own preference of tone and how loud.

bigbad69 Members Profile Send Private Message Find Members Posts Add to Buddy List Supporter of TheAMCForum Joined: Jul/02/2007 Location: Ottawa, Ont. Status: Offline Points: 6686	Post Options Post Reply Quote bigbad69 Report Post Thanks(0) Quote Reply Posted: May/25/2022 at 7:17pm
	What's your application? For street enthusiasts, sound is more important that performance., and sound is very subjective. The 2 1/2" is input or output? The output pipes doesn't need to be as large since the gases have cooled.
	69 Javelin SST BBO 390 T10

mark_k Members Profile Send Private Message Find Members Posts Add to Buddy List AMC Apprentice Joined: Jul/30/2020 Location: Kentucky Status: Offline Points: 214	Post Options Post Reply Quote mark_k Report Post Thanks(0) Quote Reply Posted: May/25/2022 at 7:51pm
	It’s on a Marlin. Going to be a cruiser. 2.5 was going to be the input pipe.

wrebelmachine Members Profile Send Private Message Find Members Posts Add to Buddy List AMC Apprentice Joined: Aug/08/2019 Location: SW Missouri Status: Offline Points: 162	Post Options Post Reply Quote wrebelmachine Report Post Thanks(0) Quote Reply Posted: May/25/2022 at 8:09pm
	There is a guy not too far from me using moroso mufflers. Sound good and the car runs real well

Repsolroger Members Profile Send Private Message Find Members Posts Add to Buddy List AMC Nut Joined: Aug/23/2021 Location: washington Status: Offline Points: 376	Post Options Post Reply Quote Repsolroger Report Post Thanks(0) Quote Reply Posted: May/25/2022 at 8:21pm
	I got flow masters 40s on my 300 with no cats full length BBK headers ...my girlfriend thinks its loud....but I don't think so...has the low rumble sound... But when you go WOT...then it sounds good😄....but on my javelin I plan on using flow master 10s....so I can be loud and proud....all the time..!!!!
	1969 sst javelin restomod

Trader Members Profile Send Private Message Find Members Posts Add to Buddy List AMC Addicted Joined: May/15/2018 Location: Ontario Status: Offline Points: 6913	Post Options Post Reply Quote Trader Report Post Thanks(0) Quote Reply Posted: May/25/2022 at 8:26pm
	Dual exhaust on a stock 327, 2" pipes are plenty. 310 CFM per pipe and supports 289 HP. Easier to work with. Would put in an "H" and not an "X" if doing a crossover. 2-1/4" pipe will support 370 HP. Would not go 2-1/2" unless you fabricate up some headers. Certainly not going to get them "off the shelf". Could go 2-1/4" to the mufflers and 2" the rest of the way. That would be plenty.

FSJunkie Members Profile Send Private Message Find Members Posts Add to Buddy List AMC Addicted Joined: Jan/09/2011 Location: Flagstaff, AZ Status: Offline Points: 4742	Post Options Post Reply Quote FSJunkie Report Post Thanks(0) Quote Reply Posted: May/26/2022 at 12:35am
	A 2.5-inch single pipe or 2-inch dual pipes will allow a 327 to reach it's full power potential. Going larger than that won't produce more power, nor will it produce less power or torque. It'll just cost more, make more noise, and be hard to route. It's very hard to fit dual mufflers under these cars unless they are small tubular glass pack mufflers (loud as heck) or hang very low to the ground to scrape things. It's generally best to use one dual-in, dual-out muffler behind the axle in the stock location. A Flowmaster muffler will give you a deep, bassy roar while a turbo-style muffler will give you a smoother, medium tone that is less obtrusive inside the vehicle. A couple of glass packs further forward in-line with the main muffler will quiet it down significantly so you have all the flow but less of the noise. No matter what you do, larger pipes or more pipes will be noisier than the original 2-inch single pipe.
	1955 Packard 1966 Marlin 1972 Wagoneer 1973 Ambassador 1977 Hornet 1982 Concord D/L 1984 Eagle Limited