Muffler replacement recommendation please

My 1978 308 GTB had a "minor" overheating problem. A custom car fella restored the damage to the car and built a new muffler to the precise dimensional specs of the original. I was hoping to save money and the new muffler with CA-legal cats only cost about $1,200. The car runs well BUT, when decelerating, it is too damned loud because of the popping of raw, un-burnt gas (like a 250 MM downshifting on a race course). Factory mufflers seem to be as rare as hens' teeth so I am considering the Tubi muffler described in the following link. I don't mind a louder cruising volume but need to "muffle" the burning of raw fuel reaching the muffler. So, has anyone had experience the this specific replacement adapting to cats? Your comments and recommendations are appreciated. Chaz

https://catalogue.tubistyle.it/ferrari/308-gtb-gts-1975-1980/mufflers/308-gtb-e-dino-308-gt4-exhaust-w-double-cat.html
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PS: Had I not had a Halon (now Halguard) fire extinguisher, my car would have burned to the ground.

 

"Is it possible that whatever set the old muffler on fire is still a problem?"
NO, that problem was solved. My former mechanic installed an MSD ignition system to run with with the stock coils. The new system was too hot for the coils. Eight years ago, the front coil burned up and caused an explosion in the front header. $$$! It was replaced without consideration of why it happened. Three years ago the other coil burned up causing 4 cylinders of raw fuel to go into the muffler. "Fire!" I was too trusting.

The car was repaired by Larry Ruth, a custom car-hot rod guy, who installed coils compatible with the MSD system. In addition to repairing all burn damage and doing a fabulous repaint on the rear panel, he built the hot rod muffler that weighs only about 25 pounds. The car ran well but popped loudly on deceleration. He explained there is always a small amount of fuel and O2 running through the cylinders (think back to Chemistry) to the exhaust and the heavy factory muffler conceals the popping. I was so frustrated that I sent the car to Andy Falbo this year and he returned it to its original 1978 ignition system configuration and further tuned the carbs. It runs better than ever now but there is still popping on deceleration. What I need is more muffling! Andy agrees but I can't find a used muffler.

There's a video on Youtube in which the driver shows off the Tubi sound in his 308. Popping is still there but it is very muted, tolerable and sounds good, the way a Ferrari should sound.

"I use the cat to get the car smogged, thats it." Yep, I used to go to my shop and swap mufflers in my Testarossa every 2 years for smog tests but it became a pain in the butt (too big and heavy). If the above Tubi works with catalytic converters, I'd install it and never worry about changing it again.

This is way too long! I will appreciate further comments but I better contact a Tubi dealer and ask them a few questions and try to get referrals. Thanks guys.

 

I had forgotten about Nick, and hanks for the reminder! I've dealt with Nick in the past and he's full of info and good stuff.