Hey, im looking to put a cat back system on my 98 xlt, 4.2 4x2. I could use any information possible about what to use. I know i dont want to run any strait pipes, but what sytem do i use. If you have a 4.2 plz tell me what u got and if you are pleased with it. I would also like to know what everybody thinks about high flow cats, any info would be helpfull thanks, taylor

ps what is that si/do or whatever, whats the diff with TRUE duals

 

I have the 50 series delta flow si/so. I love it, I had the 40 series which sounds good on the 4.2, and loved it, but it was too loud towing my 19 foot boat, but other than that sounded great, now i have the 50 series delta flow which isnt as loud, but sounds good towing, and isnt annoying like the 40 series. you dont want to go duals on the 4.2, you will loose to much power, thats what i have herd, and what i read when i was researching it, also go with 2.5" pipes. true duals is 2 mufflers which wouldnt sound good on the 4.2l, but if you want sound, go 40 series origional....

BTY, single in dual out is using one muffler while true duals is using 2...

 

SI/DO is one muffler with a single inlet going in and two outlets for pipes going out. DI/DO is a single muffler with two inlets and two outlets to be used with true duals. SI/SO is of course one going in and one coming out and can be used as a single muffler or two may be used on a true dual set up, preferably with an H or X pipe to balance gasses.