Wes Duenkel
December 1, 2017

By today’s standards, the stock 5.0s between the strut towers of 1982-1995 Mustangs won’t set any horsepower records. But, that doesn’t mean they aren’t fun! The age-old pushrod design is simple and inexpensive to modify, making it a perfect entry-level Mustang project.

We wanted to add a thumpy idle to our stock 1995 Mustang GT 5.0, so the classic Ford Performance Parts “E303” camshaft instantly came to mind. Readers of a certain age will recall that it was the go-to grind for street/strip Mustangs when a 12-second 5.0 Mustang was all the rage. Fortunately, the E303’s 110-degree lobe separation angle is friendly to the factory EFI on mass-air-sensor-equipped Mustangs.

Summit Racing Equipment had everything we needed to swap camshafts on our trusty SN95 in their convenient “Summit Racing Camshaft and Lifter Pro Pack.” Part number CMB-08-0029 covered all the bases: E303 cam, new roller lifters, all the necessary gaskets, and even assembly lube.

In addition to the E303 camshaft, Ford Performance also recommends swapping out stiffer valve springs to accompany the bump stick’s higher-revving nature. (Most aftermarket heads have such springs, but our bone-stock 5.0 still had the flimsy OEM springs atop its stock iron heads.) Summit Racing also had the springs we needed in the Trick Flow 2500100 Valve Spring Upgrade Kit.

While we waited for the brown truck to show up, we headed to Boost Addicts in Madison, Tennessee for baseline power numbers on their in-house Mustang dynamometer. Our mostly stock 5.0 (with aftermarket exhaust and underdrive pulleys) made a respectable peak 207 horsepower and 263 lb-ft of torque through the stock AOD transmission.

A follow-up test session on the Boost Addicts dyno revealed that swapping in the E303 cam into our otherwise stock 5.0 didn’t add much power. To be exact, we gained a whopping 4 peak horsepower at 5,000 rpm, but lost 8 lb-ft of maximum torque at 4,050 rpm. Considering that the rest of our trusty pushrod 5.0 was completely stock, down to the paper air filter, the results weren’t surprising. Clearly, the bottlenecks in the factory 5.0 HO combination are elsewhere and we plan to do address that with some subtle modifications in the future.

Besides, the choppy idle makes the car a hoot to drive, and we now have the right camshaft to make the most of future modifications. Check out the accompanying photos and captions for tips and tricks to make your cam swap a snap.

1. Summit Racing’s Camshaft and Lifter Pro Pack and Trick Flow’s Valve Spring Upgrade Kit got us everything we needed to swap a nostalgic E303 cam in our 1995 Mustang GT.

2. Before turning any wrenches, we took our SN95 over to Boost Addicts in Madison Tennessee. Co-owner David Hines and tuner Shannon Taylor made sure our stock 5.0 didn’t break their in-house Mustang chassis dynamometer (sarcasm, folks) with 207 horsepower at 5,350 rpm and 263 lb-ft of torque at 3,750 rpm.

3. Removing the camshaft with the engine installed in our SN95 chassis required removing the radiator and the air conditioning condenser. (If you’re A/C system isn’t busted like ours, be a responsible human and take your car to a local A/C specialist to have the refrigerant recovered.) Because our car’s refrigerant had long since leaked from its damaged A/C system, we got right to work.

4. Next, we removed the accessory brackets from each side of the engine. Using a power steering pump pulley removal tool from a local auto parts store, we separated the power steering pump from the bracket and laid the power steering pump to the side of the engine bay.

5. After removing the distributor and upper intake manifold, we removed the lower intake manifold.

6. We used a puller to remove the harmonic damper and timing cover.

7. Using the Summit Racing box in which our parts were shipped, we organized the rocker arms and push rods so we didn’t mix them up during reassembly.

8. Since we were changing the valve springs without removing the heads, we bought a pneumatic valve holder from our local auto parts store to pressurize each cylinder and keep the valves from dropping while we changed valve springs.

9. With air pressure holding the valves in place, we used a valve spring removal tool to compress the valve spring. A magnet helped us remove the OEM valve locks.

10. With the stock valve springs removed, we checked the valve spring installed height with the Trick Flow Valve Spring Upgrade Kit. With the valve spring retainer, and locks in place, we added and removed shims until the gauge fit properly. Note: Even though they look similar, there are different valve spring retainers for the intake and exhaust springs. If the gauge isn’t even close to fitting with a few shims, you might’ve mixed up the retainers. (Don’t ask how we know this.)

11. After we sorted out the necessary shims we needed, we installed the valve seals included with the Trick Flow Valve Spring Upgrade Kit.

12. Then, we placed the Trick Flow valve spring and retainer over the valve.

13. Using our valve spring compressor, we installed the Trick Flow valve locks. We repeated the procedure for the next fifteen springs.

14. With the valve springs installed, we removed the OEM lifters.

15. Using a long bolt as a handle, we carefully removed the stock camshaft. It’s important to use a delicate touch as to not nick the camshaft bearings with the sharp edges of the camshaft lobes.

16. Before installing the E303 bumpstick, we slathered the lobes with the assembly lube included with the Summit Racing Camshaft and Lifter Pro Pack.

17. Then, we carefully installed the E303 camshaft.

18. With the camshaft installed, we lubricated and installed the new Ford Performance Parts roller lifters that were included in the Summit Racing Camshaft and Lifter Pro Pack.

19. Before reinstalling the stock rocker arms, we applied some of the supplied lubricant to the pushrods and valve tips to help reduce wear and on initial startup.

20. Older engines usually have paper or cork oil pan gaskets, which need to be cut where indicated. Our engine had an OEM steel-reinforced silicone gasket that was still in good shape; we decided to reuse it with some silicone sealant.

21. After installing the supplied front cover crankshaft and oil pan seals, we applied some silicone to the corners, where the seals meet the gaskets.

22. We also squeezed some silicone in the harmonic damper keyway to prevent oil leaks.

23. We used a harmonic damper installer tool borrowed from our local auto parts store to press the damper onto the end of the crankshaft. Note: even though it’s tempting, do not use the OEM damper bolt to install the damper! Using the damper bolt is a great way to strip the threads and ruin your crankshaft.

24. Coolant leaks suck, so we used some gasket sealant around the coolant ports of the included intake gaskets to keep a leak from ruining our day.

25. The combination of the lumpier cam and AOD transmission would occasionally stall the engine. To increase idle stability, we installed an idle air control adjuster from Late Model Restoration Supply.

26. The idle air control adjuster includes an adjustment screw to tailor the amount of air that “bleeds” past the idle air control valve. It did the trick to stabilize the idle and prevent stalling.

27. While we were pleased that the lumpy camshaft made our 1995 Mustang GT more fun to drive, the dyno results were a bit of a letdown. We gained 4 peak horsepower at 5,000 rpm, but lost 8 lb-ft of maximum torque at 4,050 rpm. The power was disappointing, but not surprising considering that our trusty pushrod 5.0 was otherwise bone stock, paper air filter and all. To add meaningful power to our pushrod 302, a good pair of cylinder heads and better intake manifold would go a long way to utilizing the E303 cam’s more aggressive profile.