The exhaust system begins at the manifold and header and determines your engineâs personality at the tail-pipe. Chances are good that if youâre reading this book youâre also interested in performance. Because this is an âinterchangeâ book, the focus here is on stock to mildly modified exhaust parts and installation.
This Tech Tip is From the Full Book, FORD SMALL-BLOCK ENGINE PARTS INTERCHANGE. For a comprehensive guide on this entire subject you can visit this link:
LEARN MORE ABOUT THIS BOOK HERE
SHARE THIS ARTICLE:Â Please feel free to share this article on Facebook, in Forums, or with any Clubs you participate in. You can copy and paste this link to share: https://www.diyford.com/exhaust-parts-interchange-for-small-block-ford/
Single- and Dual-Exhaust Systems
When the small-block Ford was introduced in 1962, the only exhaust system available was a single vanilla muffler. Even the 1963 Fairlane with a 289 High Performance V-8 had a single-muffler exhaust system. The Hi-Po didnât have dual exhausts until the Mustang received this option in June 1964.
The aftermarket offers exhaust systems for all Ford generations. National Parts Depot, Virginia Classic Mustang, Mustangs Unlimited, and Dearborn Classics, to name a few, offer a generous lineup of bolt-on exhaust systems that you can install yourself or have installed. Flowmaster, Borla, Magnaflow, Walker, and others have extensive muffler product lines.
If you own a classic Fox Mustang or perhaps a mid-1980s LTD or Thunderbird with 5.0L power, a wealth of great bolt-on exhaust system packages is available. For classic Mustangs and other vintage Fords you can select one of many off-the-shelf exhaust systems. Given a choice, opt for an off-the-shelf dual-exhaust system engineered to fit your Ford. If a system is unavailable, access to a good exhaust shop enables you to fabricate a custom-made dual-exhaust system with your favorite aftermarket muffler.
The aftermarket offers a wealth of bolt-on systems that enable you to avoid the muffler shop. Whether you have a vintage Ford or late-model Fox classic Mustang, you can install some bolt-on systems in your home garage. The two sides of a dual-exhaust system must meet in the middle with an H- or X-pipe known as a balance tube.
Purchase Considerations
While youâre shopping for mufflers, consider noise levels that can damage your hearing and irritate those who live around you. Loud and obnoxious isnât in style anymore. A soft throaty burble at your Fordâs exhaust tips is whatâs in style. So always opt for an environmentally friendly exhaust system that gets attention without being offensive.
Classic Mustang floorpan reinforcement plates are available from Classic Tube for those planning a dual-exhaust system for a Mustang or Cougar. These stampings are identical to those that the Ford factory installed on Mustangs with dual-exhaust systems, and including brackets and muffler hangers. Muffler shops tend to use sheet-metal screws to secure muffler hangers to the floorpan, which often tear out when you cruise over a bump. The Classic Tube floorpan reinforcement system prevents that, offering solid security for a dual-exhaust conversion.
This classic Mustang dual-exhaust system is from National Parts Depot. Mufflers offer a quiet mellow burble at the tailpipes. If your goal is performance, look to Flowmaster, BBK, Borla, Magnaflow, and others for mufflers that fit these two 1/4-inch pipes. Do not oversize your exhaust plumbing. Anything larger than 21â2 inches on the street is overkill; you lose exhaust scavenging velocity.
Bolt-on exhaust systems usually offer a good fit. Not all after-market exhaust systems deliver optimum fit, which is when you may have to consult with a muffler shop for pipe tweaking to clear the driveshaft or frame.
The nice thing about off-the-shelf dual-exhaust system retrofits is fit. They install with ease and you have virtually no chance of the rear axle striking the tailpipe.
Flowmaster offers a complete line of exhaust systems for 1979â1995 Fox and SN-95 Mustang GTs with the 5.0L High Output engine. All you have to do is choose the muffler type. If you like loud and obnoxious pick the Series 40 from Flowmaster. The best muffler for cabin quiet is the Series 50 Delta Flow, which offers a mellow burble.
A Flowmaster exhaust system includes mounting hardware and rubber hangers enabling you to achieve exhaust system security and quiet.
You often see dual-exhaust system retrofits with exhaust hangers and sheet-metal screws threaded into the floorpan that can tear out. Classic Tube offers original equipmentâstyle floorpan reinforcement plates for classic 1965â1969 Mustangs and Cougars. You can weld them in or use an industrial adhesive for out-standing results. The use of a good industrial adhesive saves you time and money because you donât have to hire a welder.
The Classic Tube pan reinforcement plates can be rosette welded (shown) or bonded with an industrial-grade adhesive. Never just bolt or screw dual-exhaust hangers to your floorpan because they tear out. You must have a reinforcement plate of some kind even if you have to fabricate one yourself.
Arvinode Dual-Exhaust System
One of the factory performance exhaust systems now available in reproduction form is the limited- production Arvinode dual-exhaust system installed on 289 High Performance Mustangs between October 1964 and March 1965. It was originally manufactured by Arvin Industries for Ford and is available from Waldron Antique Exhaust and is an authentic reproduction of Fordâs original system. It has two acoustically tuned straight-through mufflers and two resonators that soften the bark.
When youâre on the throttle with an Arvinode dual-exhaust system, it gives your small-block Ford a nasty bark at the tailpipes yet it is not offensive in terms of noise levels. Everything you need to install this system yourself is there, including hangers and all hardware.
These are traditional muffler and tail-pipe hangers using tire carcass rubber for noise isolation and quiet. The down-side is muffler and tailpipe movement.
This is the factory-style exhaust hanger bracket and threaded studs that fit through the Classic Tube reinforcement plate.
Once your Classic Tube exhaust brackets and studs are installed, you may choose from a variety of muffler hanger types, depending on muffler choice.
When youâre shopping for mufflers, keep overall muffler length in mind. Long mufflers do not clear Mustang and other Ford compact/intermediate floorpan pockets.
The Arvinode dual-exhaust system from Waldron Antique Exhaust is a reproduction of the original Arvin Industries exhaust system used by Ford on new 289 High Performance Mustangs between October 1964 and March 1965. This short-lived system was developed by Dave Wallace. It gives a classic Mustang that snarly bark at the tailpipe.
The Arvinode dual-exhaust system is fitted with resonators at the tailpipes to soften the bark as they were originally designed by Ford. These tailpipes have downturns as they were originally intended. They were not, however, originally available with GT trumpets.
The reproduction Arvinode system was conceived by Dave Wallace, who managed to round up the original drawings. This system makes it easy to perform an authentic restoration on a 1965 Mustang with the 289 High Performance V-8. This system was installed on factory Mustangs for a limited time, but you can install it on any 1965â1968 classic small-block Mustang as long as you have 289 High Performance exhaust manifolds. Given access to a good muffler shop, you can modify this system to work with shorty or long-tube headers.
Manifolds and Headers
Small-block Ford manifold selection has never been generous. For the majority of applications one basic type of manifold for the 221/260/289/302 was available through the 1960s. As Fords changed in the 1970s, manifolds changed accordingly. If youâre building with performance in mind chances are youâre not thinking about exhaust manifolds.
The best stock exhaust manifold for the 221/260/289/302 is the 289 High Performance version. Ideally, you find a pair for the 1963â1964 Fairlane with an automatic choke heat stove, which are decidedly rare and nearly impossible to find. The 351W and 351C were never factory fitted with high-performance exhaust manifolds, although the 351W manifolds resembled those bolted to the 289 High Performance V-8.
The poor manâs Hi-Po manifolds are those for the 351W. The 351C and Boss 302 employ similar cast-iron manifolds because both have the same cylinder head. Other than variances for vehicle application, they are the same.
If you take a more conservative path, you want short-tube headers, or âshorties.â The most user-friendly shorties are headers from Ford Performance Applications (FPA) with a ball-and-socket collector. They have the best fit of any header in the marketplace.
Small-block Ford exhaust manifolds didnât change much between 1962 and the 1970s. This is a 289-2V/4V exhaust manifold, which can be identified by casting number and date code.
Date codes are cast into the manifold. This date code is â5D23,â indicating a casting date of April 23, 1965.
Early small-block Ford exhaust manifolds had these lock tabs to secure bolts. Later, Ford used a lock washer designed to do the same thing: eliminate excessive amounts of manufacturing time and labor.
Beginning in 1985, Ford fitted the 5.0L High Output V-8 with tubular shorty headers, which was a first for factory performance. The downside to these factory shorties is restriction. They breathe better than cast iron but are still limited due to the pinched nature of the primary tubes.
The aftermarket offers a variety of locking header bolts designed to remain secure throughout extreme vibration and heat. Each offers the same kind of security with different installation technique. The header bolt and lock washer combination on the right is easier to install and remove.
These are reproduction 289 High Performance exhaust manifolds, which were something of a cast-iron factory shorty header back in the day. First-year Hi-Po exhaust manifolds had a choke heat stove for the automatic choke, which went away when Ford changed to a manual choke with the 289 High Performance V-8.
The 351C and Boss 302 engines had very similar exhaust manifolds because they have the same cylinder head. They differ in application. Boss 302 is Mustang and Cougar specific. The 351C was fitted to a variety of applications along with a taller deck block.
It is virtually impossible to find good original new-old-stock catalytic converters for late- model Fords. Nearly all after-market exhaust manufacturers produce catalytic converters and packages for late-model Fords. If you live in California or elsewhere with tough smog laws, your cats must be smog legal. Magnaflow offers complete classic Fox and SN-95 cat packages. This is a BBK cat package for 1986â1993 Mustangs.
When you compare Ford factory shorties to JBA shorty headers, thereâs a world of difference in primary tube size and restriction.
These headers look factory original because so much goes into proper fit. If you have them ceramic coated in a charcoal or natural metal finish, they vanish alongside your small-block Ford.
Ford replaced iron exhaust manifolds with short tubular headers beginning in 1985 on the 5.0L High Output V-8. This is not a header to be used for performance purposes, but instead a restoration where authenticity is important. If youâre building a classic Fox-Body Mustang restomod, a good aftermarket shorty header is the best choice, which improves exhaust scavenging and remains smog legal in most states.
Post-1975 Ford vehicles typically have catalytic converters. Stick with a good, free-breathing catalytic converter, especially if your local area has tough smog laws and testing. Magnaflow and BBK both offer California smog-legal catalytic converter packages for the 1979â1995 Mustang GT and LX with 5.0L High Output engines. These are easy bolt-on cat packages you can integrate into nearly any aftermarket exhaust system.
Thermactor System
Beginning with the 1966 model year Ford had to meet even tougher California emissions standards. Small-block Fords headed for California received the Thermactor smog-pump system. It is an exhaust emissions reduction package consisting of an engine-driven air pump, hoses, check valves, anti-backfire valve, and tubular air-injection manifolds tied to the exhaust manifolds. Air is injected into the exhaust ports to reduce hydrocarbon emissions.
Exhaust-air manifold check valves allow the flow of air in one direction only, which protects the pump when exhaust pressures become higher than pump pressure at wide-open throttle. The anti-backfire valve on early Thermactor systems operates based on intake manifold vacuum and throttle position. Failure occurs when the anti-backfire valve diaphragm or its check valves develop a leak and has to be replaced. Early Thermactor air-pump systems were fitted with a foam air cleaner element.
Although many think that the Thermactor robs power, it has never made much of a difference in stock engines aside from exhaust port restriction. The Thermactor employed a tubular air manifold for each cylinder bank from 1966 to 1974. Beginning in 1975, the tubular manifolds were eliminated and the air passage was cast into each cylinder head along the exhaust ports with external ports at each end of the head.
Ford introduced Thermactor air injection in 1966 on California cars with the small-block V-8. Thermactor appeared on some 49-state manual transmission cars. The Thermactor air pump injects fresh air into the exhaust ports, enabling continuing fuel burn on exhaust stroke to reduce hydrocarbon emissions.
This is the Thermactor air-bypass valve, which first saw use in 1968. It is designed to vent excessive air-pump pressure.
The air manifold check valve prevents exhaust pressure from backing up into the air pump. The check valve allows the flow of air one way into the exhaust ports, but not backward to the pump in case exhaust pressure becomes greater than air pump pressure under hard acceleration.
This Thermactor air pump has been installed on a 1995 Mustang GT with 5.0L High Output V-8. The pump pulley is retained with three bolts much as it was early on in 1966. From 1979 to 2001 the air pump was driven by the serpentine belt.
Thermactor parts are difficult to find. Yet, if youâre doing a restoration or must meet tough smog laws in your area, you must have the system. The Internet yields several sources for Thermactor emission system parts.
Later examples of the Thermactor system were equipped differently than those first systems introduced in 1966. Beginning in 1968 Thermactor air-pump systems were revised and fitted with air bypass valves, which were commonplace until the late 1970s.
By the 1980s, Ford had refined the Thermactor air-pump system to include air pump, air bypass valve, check valves, air manifolds and hoses, and air-control valve. This system was easier to understand and maintain because of its simplification and EEC. The 1980s Thermactor is more advanced due to its air injection at both the engineâs exhaust ports and at the catalytic converters. As necessary, Thermactor also vents air over-board, which can sometimes be heard in classic Fox and SN-95 Mustangs.
Written by George Reid and Posted with Permission of CarTechBooks
GET A DEAL ON THIS BOOK!
If you liked this article you will LOVE the full book. Click the button below and we will send you an exclusive deal on this book. 