347 Stroker Engine Build - Homebuilt Stroker Swap Part 3

Next, we installed the ARP studs to fasten the windage tray. Be sure to use assembly lube to ensure your torque settings are accurate.

Re-torque the main caps to spec using nuts provided in the installation kit.

The tray then attaches to the studs using the nuts provided. Be sure that the tray is not touching the crankshaft throughout its entire rotation before continuing.

Next install the pickup tube. Using a piece of modeling clay or equivalent, check pickup-to-pan clearance. We used masking tape on the screen as to not push any clay into the pickup tube. With the ball of clay in place, test-fit the oil pan and then remove it. Check the thickness of the clay. There should be between ¼ and 3/8 inches of space between the pickup screen and the pan—ours was exactly 3/8 inch. Depending on application, you may need to bend the tube slightly or modify the windage tray to accept the pickup-tube mounting tab.

Next, install the timing cover. Be sure the inside is clean, and don’t overdo it with the silicone around the coolant ports. Excessive use of sealant will restrict coolant flow to the engine. Also, make sure your alignment dowels are in place and the bottom is flush with the oil pan mating surface on the block.

Then install the oil pan. Be sure to slowly tighten all the bolts in stages so as to not bend the pan or damage the gasket during installation. Though our pan kit came with a four-piece gasket, we opted to use the one-piece rubber gasket from Felpro, which came with our engine gasket set. Also, be sure the front and rear ends of the gasket fit into the grooves on the timing cover and rear main cap respectively.

Next, it’s time to install the harmonic balancer. Summit Racing Equipment sent us this Ford Racing balancer (PN M-6316-C351; $249.95) and ARP bolt kit (PN ARP-150-2501; $20.99).

Summit also sent us a steel underdrive pulley kit from March Performance (PN MCH-1000-08; $53.95). When installing the balancer, it’s a good idea to apply some antiseize to the crankshaft mating surface for easier removal later. You should also apply some red high-strength thread locker to the threads on the balancer bolt and torque to spec.

Since the stock flexplate was balanced for a 50-ounce imbalance, we had to upgrade to one with a 28-ounce imbalance to match our new engine. We went with this one from the Platinum Xtreme Series from Performance Automatic (PN PA26467). It features SFI SPEC 29.1 and retails for $215.21.

We then installed our lower intake, as well as this set of new 30-lb/hr injectors from Summit Racing Equipment. Made by Ford Racing Performance Parts (FRPP), the injectors (PN FMS-M-9593-BB302; $239.88) will provide more than enough fuel to feed our 347.

After re-installing our valve covers, headers, and engine mounts, we lowered the new engine in place. Thanks to helper Buddy Christ, it fell right into place.

Summit Racing also sent us some fresh hoses and tune-up parts from FRPP. The hose kit (PN FMS-M-6052-B; $159.95) comes with high-temp silicone radiator and heater hoses, and all new clamps. The spark plug wires (PN FMS-M-12259-C301) retail for $41.95; the distributor cap and rotor (PN FMS-M-12106-B302) go for $45.95.

Since we upgraded from 19-lb/hr injectors to a 30-lb/hr set, we had to upgrade the MAF to match.

Since we’re sticking with the BBK cold-air intake and the old meter worked fine, we called BBK Performance for a new 76mm MAF (PN 8005; $229.99) calibrated for our new injectors.

We used an air drill and oil system priming tool to prime the oiling system before installing the distributor.

Since we were previously using a 65mm throttle body with the stock EGR plate, we decided to upgrade to a larger throttle body and spacer. Summit Racing sent us its 70mm polished throttle body (PN SUM-227201; $171.95) and matching EGR plate (PN SUM-227507; $61.95), shown here.

We transferred the IAC valve from the old throttle body and installed it with the new gasket included with the throttle body.

We then fashioned a block-off plate for the EGR using a piece of sheetmetal. It can be installed onto the EGR plate using the provided EGR gasket and some silicone sealant.

With the EGR plate installed, we installed the throttle body gasket and then the throttle body. After making a best of 341 rwhp and 337 lb-ft of torque with the 65mm throttle body, Chris Johnson of SCT adjusted the tune on our chip for the 70mm throttle body and spun the rollers to 350 rwhp and 345 lb-ft of torque. Next up was the big 75mm throttle body and spacer.

Since the inlet of our Edelbrock Performer RPM II intake was only 70mm, we had to hand-port it to accept the larger throttle body. Johnson marked the opening using a permanent marker and the EGR plate gasket for the 75mm plate.

He then used a die-grinder to slowly grind away the excess aluminum until the red line was completely gone...

… followed by a paddle-wheel sanding disc to smooth the opening.

After Johnson made some changes in the tune for the 75mm throttle body, we made another pull on the Dynojet. The result: 353 rwhp and 346 lb-ft of torque—3 hp and 1 lb-ft of torque better than the 70mm run, and a difference of 12 rwhp and 9 lb-ft from the 65mm run.

As you can see, the opening is smooth and round. If you don’t open the intake, then you won’t see the full potential of the larger throttle body.

After installing the 75mm throttle body (PN SUM-227202; $171.95) and EGR plate (PN SUM-227502; $61.95), Johnson adjusted the TPS. The signal voltage (green wire) at closed throttle should be less than 1 volt. There is an adjustable mount built into the Summit Racing throttle bodies to make this adjustment easier.

Here’s a graph showing N/A before and after, as well as before and after on the 125-shot of nitrous. The peak power N/A before was 276; now peak power is 353—a 77hp difference. Before, on the spray, it made 353 rwhp and 372 lb-ft; now it makes 422 rwhp and 425 lb-ft of torque on the juice.

What really makes us happy, though, is this graph. Run 19 shows peak power before on the 125-shot of nitrous—353 rwhp and 372 lb-ft of torque. Run 41 is N/A with the new 347—353 rwhp and 346 lb-ft of torque. With the exception of a peak torque loss of 26 lb-ft, these two runs are fairly equivalent. Though we should probably just be happy that we don’t technically need the juice anymore to achieve 11-second quarter-mile e.t.’s, we’re going to track-test it both ways—maybe we can break into the 10s on the spray! Check back next month with a full track-test report.