SLP Performance has long been known for their high-quality performance products, not the least of which is their Loudmouth catback systems. SLP currently offers headers, x-pipes, and catback exhaust for the late model Mustangs and they’ve recently just turned their attention towards the 1986-’93 5.0 Mustangs as well. We install and review their latest catback for the 5.0L Mustangs.
SLP Performance has long been known for their high-quality performance products, not the least of which is their Loudmouth catback systems which were initially offered for GM vehicles and have now expanded to the Mustang arena.
SLP currently offers headers, x-pipes, and catback exhaust systems for the late model Mustangs and they’ve recently turned their attention towards the 1986-’93 5.0 Mustangs. We at Pro3i had an opportunity to install one of these new catback systems. Our test-mule for this installation would be our in-house ’85 GT, which because of its body-style uses the LX version catback -SLP-31015 (1987-93 GT systems use part number SLP-31016).
The complete Loudmouth kit from SLP
We began by unpacking our SLP catback system and checked our inventory using the supplied SLP Packing List check sheet, we allowed our Mustang plenty of time to cool down and then began unbolting its current exhaust.
This SLP system utilizes mandrel-bent, 304 grade Stainless Steel material, which is an even higher grade of stainless steel than the more commonly used 409. Both mufflers (resonators) and SLP-etched, double-walled exhaust tips are show-polished stainless steel, delivering performance and great looks.
We found the install to be among the easiest we have ever encountered. The SLP instructions are extremely easy to follow and we didn’t have any fitting issues whatsoever. The tubular SLP Loudmouth mufflers also allowed for more driveline clearance than other systems have in the past and the heavy-duty band clamps provided are far superior to standard exhaust clamps and do a fantastic job without the worry of fatigue. SLP even goes through the trouble of including new exhaust hangers in their kits.
Mounting the intermediate pipes and resonators
Bolting the remaining tailpipes & tips into place
We began the install by bolting the new exhaust hangers into position and hung the mid-intermediate pipe, next we slid the muffler into the inlet of the mid intermediate pipe and then slid the front intermediate pipe onto the inlet of the muffler (resonator) and bolted that to our H-pipe. We kept everything lose enough so that final adjustments could be made. We then slid the tailpipe onto the mid intermediate pipe where it comes over the axle, slid the exhaust tip on and slide the hanger into the factory rubber hanger. We then adjusted everything where we needed it to be making sure that we allowed for plenty of clearance. After a final tightening of our catback we gave it all a last once over and then reached for the ignition.
Aligning the tailpipes/tips before final tightening
Polished, double-walled, 3.5″ tips w/logo
Our Loudmouth system crackled to life with the turn of the key, and shook our shop with a stab of the gas, this system is clearly louder than any other catback we’ve ever had on this car . When SLP says its loud, you can definitely take their word for it, so be prepared to get some stares and don’t say we didn’t tell you so – the Loudmouth lives up to its name!
We were impressed with the overall construction, fit and finish of this 5.0 Loudmouth catback and it’s unique, threatening sound got us plenty of attention. So, if a mean, aggressive sound is what you’re after the Loudmouth catback easily meets the criteria. Loudmouth resonators offer virtually zero flow restriction and deliver an angry growl at the blip of the throttle! But SLP didn’t stop there, if you desire something not as loud, SLP’s modular design allows customers to simply purchase Loudmouth II mufflers and swap out for a quieter exhaust note. The Loudmouth II mufflers offer flow and performance similar to SLP Loudmouth resonators but feature a ceramic-wrapped, perforated core that reduces high-frequency noise and in-car resonance. So take your pick, SLP has ya covered!
Categories: Mustang Tech