Different between 84 and 85 Mustang 5.0 exhaust?

[JACook]

It's a question of degree. Exhaust upgrades are largely why the mid-'85 CFI GTs had about 15 HP more
than the '84s. The engines were otherwise the same. The '85 CFI engine used the same shorty headers
as the 4V engines, and while the Y-pipe was different, it was the same diameter. Both used the same
main catalyst bed, but with a different connection to the Y-pipe.

I don't know that the '85-style headers and Y-pipe, with a larger diameter single exhaust wouldn't get you
most, if not all, of the improvement, vs running dual mufflers and tailpipe.

[xctasy]

Yes, it's worth it. The 5.0 is super responsive, probably the CFI more than the 4180C and port EFI due to the way aged stock cat singles restrict an electroncially managed engine.

Fords net horspower levels for pre emissions 2-bbl 289 and 302's were about 175 hp net (2-bbl German T5's for the 1964 to 1971 era which were listed as 195 to 200 hp gross packages in the US were rated at the level yours is now. The 225 gross hp 4-bbl engines were rated at 190 hp net). This is exactly where the 1982-1985 5.0 engines ended up. The Draconian CA versions of the Federal emissions took Ford 18 years to master, and then they aced the class. Even a Cali1969 Boss was really a 290 hp net engine, but with an air pump and 290 degrees of duration. Your car is subblime, but free of all the complication that goes with upgrading an EFI engine.


http://www.at.ford.com/SiteCollectio...brochure_2.jpg

Anytime the induction and exhaust was upgraded, the Windsor engine shot off in its power level. Its very responsive to the right gear...any intake, exhaust, gearing and cam increase yeilds similar gains as it did in the halcyon days of the 60's and 70's. The 2-bbl intake twin injector CFI can flow up to 350 hp with the right injectors and intake manifold and fuel delivery stratergy. There are 8.7:1 289 engines which make 350 hp with just one 500 cfm 2-bbl carb.

From 1981 to 1987, Ford pushed real hard to make the 5.0 a better package. Each detail Jeff listed was the factory solution to herald in 225 hp by 1987. Five modifications to get 200 hp? Take the advice above, blend the flapper in too.

You'll end up with a very good dual exhaust system, and just need to integrate the intake manifold heating part.

The deal is that Ford was able to get excellent horspower increases ( it was formerly a 120 hp CFI system which was basically October 1979 5.0 spec, but with an even better managment system).


Everything else was tried and true, still have good part support.


I don't know of any speed density managed engine which will effectively cope with a such a horsepower increase.

[LftTrnLdy]

I realize this thread is kind of old, but I'm putting my stock '84 back together and finding a hard time locating stock exhaust replacement items. For some reason, Rock Auto, Autozone and most everywhere I look expects it to be dual exhaust, yet I read in this thread exactly what I have. Single cat, Single muffler, tail pipes are missing, but I believe it did have the twin pipes at the back because me being a silly girl thought it actually had duals until I got underneath. Is there anywhere to find the stock replacement pipes or will I just need to go to a muffler shop and have them made? Everything is still usable from the engine to the back of the cat.

[Saturn V]

I realize this thread is kind of old, but I'm putting my stock '84 back together and finding a hard time locating stock exhaust replacement items. For some reason, Rock Auto, Autozone and most everywhere I look expects it to be dual exhaust, yet I read in this thread exactly what I have. Single cat, Single muffler, tail pipes are missing, but I believe it did have the twin pipes at the back because me being a silly girl thought it actually had duals until I got underneath. Is there anywhere to find the stock replacement pipes or will I just need to go to a muffler shop and have them made? Everything is still usable from the engine to the back of the cat.

84 5.0 had the single muffler and exhaust all the way back to a twin-tip exhaust that exited on the driver's side, so it's a true single exhaust system. In 85, behind the main cat the exhaust split into two mufflers and single tips on each side of the car. So 85 had a semi-dual exhaust. You could go either way at this point. In the Parts-For Sale section there is a member selling the y-piece that can be used to split the single exhaust after the main cat into two pipes to go into two mufflers, 85-style (btw ... he mentions 84 in his ad, but I've never seen an 84 that used that piece). I think you could then buy the replacement dual-exhaust tail pipes that are sold for 85-93 cars ... lots of different brands for these available now. If you go this route, as discussed in this exhaust forum many times, you'd need to do something to relocate the rear rubber brake line hose to keep it from getting scorched by the later model passenger side tail pipe ... this is a real safety issue.

Or you could keep it 84-style, like I did, and try to find an original single/twin-tip exhaust (not easy to find, but they do show up occasionally) or get a reproduction one (not exact, but close) from Stinger Performance (scroll down to SVO Dual Angle Cut Exhaust Tip on that site or see pic below). Or just get some generic tip. It all depends upon how original you want to look and your budget. Good luck!

[Mavereq]

I have one of those tips. I have no idea what it's worth but I don't plan to use it.

[JACook]

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