i been workin on puttin duel exhuast on 1984 Ford F-150...i have 1 straigh on it w/ cherry bomb or glasspack add 2 it by weld... believe me it sound awsome but i dont like look of single and bein that loud... no one believe me that i have single pipe till they look under the truck... i think if i could get duels on it It would b even better..so here is my problem im runnin in2 is that the 1980's F-150 have low gas tank 22 ga... then drive shaft rite next 2 it...so i cant run straigh duels the way i like 2...i have cut my exhuast now where its 15" be4 rear axle which gas tank ends... how can i run duels from there and make it still sound mean? i have trailer hitch in back also thats 33" across rear of truck....so what do ya yall think? how?

Red, I'm not familiar enough with the 1984 F150 to know if there's room under there for a second muffler. If that's what you're after.
If all your after is the duel look, any competent muffler shop should be able to do that for you.
If that's the case almost all the after-market companies, Flowmaster, etc make single in, duel out or duel in, duel out mufflers. Whatever you need.
I originally had a Flowmaster 40 series single in, duel out put on my 3.0L Ranger. Had a number of folks tell me they thought it sounded like I had a V8 under the hood.
I didn't think it did, but that's what they said. It was much to loud for me (but then I'm 69) and the in cab resonance drove me crazy.
So I took off the Flowmaster and replaced it with a Magnaflow. I had a muffler shop bend the pipes for me so that I now have four (4) exhaust tips out the back.
Check around with a few shops in your area. It shouldn't cost that much. Or if you have access to a pipe bending machine you might give it a try yourself.
You should be able to find the mufflers on Ebay for about $70-80.

Here's what the back of my truck looks like. Click on the photo to "super-size" it.

Moderator,
thanks for ur word on it...i hate 2 tell i add masterflow muffler after my glasspack and then i make i quit and i mean really quit...is it polly i put it wrong way...but i cant finger it out so i could it off...im goin 2 nigger rig in y pipe 2 see how that works...but thanks for ur words....