What’s Old Is New Again: The Retro 5.0 Top End Comes Together

What’s Old Is New Again: The Retro 5.0 Top End Comes Together

Last month, you saw the bottom end of our 5.0-liter HO engine project come together with some modern parts. But it was still true to the time period of the ‘90s. In that same vein, this month we move on to the top end of the engine . Remember, we are putting this engine together to be a dyno mule, as we test traditional modifications with a modern twist, slowly bringing the Retro 5.0 solidly into the 21st century.

Starting With The Heads

Starting off with the obvious, as a starting point we reused the original cylinder heads. The iron E7TE heads are far from a performance cylinder head, with small 127cc intake ports, 1.78-inch intake, and 1.46-inch exhaust valves. Our particular set has chambers measuring 61cc, meaning they might have been surfaced at some point, but is still well within the range usually seen from the factory. With somewhere in the neighborhood of 160cfm of flow, these heads will be one of the first things to go after our baseline is established.

To ensure we give the E7 heads the best possible chance, we pulled the valves out, checked them all for straightness, cleaned them up, and then lapped them into the valve seat. After degreasing the ports as best we could, we then installed the new valve seals included in our MAHLE gasket kit.

The valves, retainers and locks for Retro 5.0's core engine were all reusable after a quick cleaning in Berrymans. We lapped the valves into the heads for good measure, and replaced the almost-thirty-year-old valvesprings.

In order to be as correct as possible, but not reusing almost-thirty-year-old valvetrain components, we turned to our friends at Melling for some new OEM parts. Since they offer pretty much every OEM component in the valvetrain of Retro 5.0, it was a no-brainer. We started with a set of Melling’s OEM-replacement valvesprings (P/N: 466444) held in place with the chunky OEM retainers.

To attach the heads to the block, we used a set of MAHLE’s OE head bolts (P/N: GS33316), along with the .040-inch-thick head gaskets included in MAHLE’s OE gasket set (P/N: 95-3447). Since MAHLE’s replacement bolts are torque-to-yield bolts, we had to take the extra step of measuring torque angle. But, luckily, our digital torque wrench has that function built-in, and final torque angle was 90 degrees, making it a simple process.

Trust, but verify. The specified seat pressure for the Melling springs is 106 pounds, with 209 specified at .500 lift. We measured at our cam's peak lift of .451 inch, and came in about 187 pounds of open pressure.

Before the heads were installed, we lubed up and dropped in a set of Melling’s hydraulic roller lifters (P/N: 466444) which are retained by the original Ford dog-bones and lifter spider. Then, we added a set of Melling’s OEM 5/16-inch pushrods (P/N: MPR-366) and topped it all off with 16 of Melling’s rocker arm kits (P/N: MRK-548). The kit contains not only a brand new cast 1.6:1 slider-tip rocker arm, but also an OEM-style pedestal mount and the pedestal bolt.

This setup gives us a factory-fresh set of E7TE cylinder heads, exactly as they came from the factory, for our baseline.

A quick presoak in engine oil and the melling replacement roller lifters slid right into the lifter bores. We reused the factory dog bone and spider retainer setup.

Topping Off The Combination

As you might remember from the previous article, this engine is out of a 1993 Thunderbird. While almost identical to the 5.0L in the Mustang of the same vintage, it did have a different intake manifold. The lower-profile design allowed for increased hood clearance in the MN-12 Thunderbird and made its way into the 1994-’95 5.0L SN-95 Mustang. However, we chose to instead go with an actual 1993 Mustang intake manifold, paying way too much for one on eBay.

The previous owner had attempted to color-match the upper intake to Tropical Yellow exterior paint. The attempt did not withstand the test of time, so we power-washed the upper and lower intake manifolds and rattle-canned the upper a nice shade of smoke gray. Once that was all dry, we dove back into our MAHLE gasket box and grabbed both the intake gaskets and the china-wall gaskets.

The MAHLE head gaskets are part of the OE gasket set and measures in at the factory .040-inch compressed thickness.

Luckily for us, Milodon sent over one of their complete engine bolt kits for Retro 5.0, so we weren’t forced to reuse the aged factory hardware, and were able to bolt down the intake manifold with shiny, fresh yellow-zinc-coated bolts. The MAHLE kit includes several different lower-to-upper gaskets, so grabbing the correct one, we attached the upper with four 1-3/4-inch long 5/16-inch coarse (5/16-18) bolts, and two 6-inch long bolts. (Pro tip: the six-inchers can be hard to find locally, especially in yellow-zinc Grade 8 to match the intake bolts, but Tractor Supply saved the day.)

The Melling rocker arm kit includes everything that you need to replace old and worn rocker arms — rocker arm, pedestal, and bolt are all included. The stock replacement 5/16-inch pushrods measure 6.248 inches long and are rated to 300 pounds of spring pressure.

With the heads and valvetrain on, and timing double-checked, we were able to bolt on the new timing cover we ordered from Late Model Restoration, and install our Fluidampr balancer. As you might remember, we discussed the issue of external counterweights with Fluidampr here. We installed our 50-ounce imbalance, SFI-approved damper on Retro 5.0 using a balancer installer, and it went on like a glove, since the machine shop had already ensured the hub had the optimal press-fit. The nice thing about the Fluidampr unit is that the two-piece design allowed the balance shop to separate the balance ring from the hub and balance our assembly with our actual unit, rather than an analog. The Milodon engine bolt kit also included a new crankshaft bolt and washer, but we the washer’s diameter was slightly too large for the Fluidampr hub, so we used the OEM washer on the new Grade 8 bolt.

Lighting Fires And Kicking Tires

For the ignition system, we were in a bit of a dilemma. We had the factory distributor and coil from the engine, but they had seen much better days. OEM replacements are more expensive than we expected, so we decided rather than spend money twice, we’d just do it right the first time, and went with a Performance Distributors OEM-style (as opposed to their popular DUI setup) hot-forged distributor, Screamin’ Demon ignition coil, and LiveWires spark plug wires — in Ford blue, of course. We’ll be diving more deeply into those components in an upcoming article, so stay tuned for that.

Retro 5.0 long-block

Here, you can see the repainted upper intake manifold, the new timing cover from LMR, and how nicely the Fluidampr fits with the stock timing pointer. We still have to figure out how we’ll mount the ignition coil for the dyno.

To light off the cylinders, we planned ahead. You might recall the spark plug indexing article we did a while back with Brisk Racing. For that, Brisk sent us a range of plugs for Retro 5.0 to run in our various dyno configurations. For this first setup, we’ll be running the Brisk Silver Racing plug (P/N: HR15YS). The silver electrode should provide a powerful spark by being more conductive with less resistance, while the “15” heat range should be perfect in this stockish application.

The Brisk Silver plugs feature a silver center electrode. Silver offers an extremely high electrical conductivity while still lasting a decent amount of time under hard use.

For the exhaust, we again made a slight concession right out of the gate. Since it’s no secret that we’ll be dyno testing the GT-40P top end soon, we are going to need “P”-specific headers for that. In order for the comparison of the GT-40 top end and the E7 top end to be truly fair, they both need to run the same headers. Since GT40P headers will work on E7 heads, we turned to JBA to see what our options were.

Since most of the P-specific headers for the Fox Body have been discontinued, we were pleasantly surprised to learn that JBA still manufactures a set of shorty headers specifically for the GT-40P heads (P/N: 1650S-2). They are manufactured from stainless steel, with 1-5/8-inch unequal-length primary tubes, with a fire cone merge collector.

Here you can see the JBA GT-40P headers compared to the stock E7 headers. Besides looking much freeer-flowing, you can see the merge collectors which add to their performance. Of note, is the collector location. Since these headers are designed for a 1965-'73 chassis instead of a Fox Body, the outlet is at a slightly different spot.

Because they are designed to fit 1965-1973 Mustangs, the collector location is slightly different than shorties designed for a Fox Body, but since we’ll be fabbing up pipes for Retro 5.0 on the dyno anyway, that is of little concern to us.

Since we won’t be using the OEM H-pipe or an aftermarket X-pipe on the dyno, we needed to come up with something to mount the oxygen sensors into. We found JBA P/N: 1650-1ST starter tubes, which are made from 409 stainless steel and match up to the GT40P headers perfectly. They also come with oxygen sensor bungs already welded in. For the dyno, they will be the perfect start to the custom dyno pipes, and once the engine goes into the car, they will be the perfect base to build an X-pipe system

Starter pipe

These JBA “starter pipes” will make a great base for the dyno pipes, and have the oxygen sensor bungs already welded in, for the two oxygen sensors used in the 5.0L.

A Little Bit Of Bling

With the intake manifold installed, we were in a similar quandary about using original parts, or upgraded aftermarket units. We could do what we did with the intake manifold, go to eBay, and spend way too much money on an OEM 58mm throttle body and EGR plate, which we’d be replacing sooner rather than later. Or, we could just go with the aftermarket units up front.

We reached out  to our friends at Steeda Autosports for some advice about Retro 5.0 (since they’ve been around since the beginning of the late-model Mustang movement). After a quick conversation with them, we had a cool plan in place. Not only did they send us a BBK 75mm throttle body and EGR (which are OG Mustang parts in and of themselves – they even have CARB E.O. numbers) but they also sent over a BBK non-fenderwell-style cold air intake.

BBK 75mm throttle body and EGR

Steeda Autosports sent us a BBK 75mm throttle body and EGR spacer kit. While we won’t be running any coolant to the EGR plate, it does function as the throttle cable bracket mounting point. The kit comes with a brand new throttle position sensor and has provisions for both the EGR valve (which we’ll be deleting for the dyno) and the idle air control valve.

Even though we won’t be running a mass-airflow sensor with our engine management (spoiler alert) we’re still being true to the configuration of the original Mustang engines with an intake tube and air filter. And thanks to Steeda, we’re doing it with the same BBK parts that were used in the ‘90s (which are still sold today).

With that, we have wrapped up most of the hard parts of the Retro 5.0 engine reassembly. Next up, we’ll sort out the engine’s accessories, the fuel system, and then sort out all of the sensors and wiring harness. Then we can hit the dyno to get our baseline power numbers.

Retro 5.0 intake

As you can see, we’re not using a mass airflow sensor with the BBK non-fenderwell cold-air intake, but other than that, this is about as period-correct as an intake setup comes. Plus, the blue matches our theme extremely well, which is a happy surprise. The intake, throttle body, and EGR spacer will follow us through all of our tests, allowing for an even comparison across the board.

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About the author

Greg Acosta

Greg has spent eighteen years and counting in automotive publishing, with most of his work having a very technical focus. Always interested in how things work, he enjoys sharing his passion for automotive technology with the reader.
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