1968 Chevy Chevelle Big-Block Swap - Cha-Ching! - PHR Project Car
From the November, 2007 issue of Popular Hot Rodding
By Johnny Hunkins
Photography by Johnny Hunkins, Steven Rupp
When we tallied up the build cost of our big-block Chevy, known 'round these parts as "The Howitzer," we thought we were nearly out of the woods with spending big stacks of cash. Building it ourselves, our 626hp pump-gas Rat cost a breathtaking $7,523.37, using a budget stroker kit from Scat, and a stock 454 block. But the act of stuffing the big rodent into our '68 Chevelle proved to be almost as disruptive to cardiac function as building it in the first place. When the cash register stopped ringing, a total of $4,861.72 had vanished, and that was after subtracting the $1,730 we got from our old big-block engine and trans. If you don't believe it, check out the chart, and see if you find any unnecessary junk on the list. You won't.
To be fair, a huge chunk of dough is allocated to a bulletproof TCI Super StreetFighter Turbo 400 trans, matching converter, Outlaw shifter, and all the other stuff you need for it, like a good driveshaft, speedo gear (with housing), flywheel, cover, dipstick, cooler, fluid, and lines. Altogether, driveline components totaled $2,854.65, including materials for a trick homemade shifter pedestal that we'll look at in a later issue. Another big bite came from a set of Stainless Works 1 7/8-inch headers, and a Stainless Works dual 3-inch stainless X-pipe exhaust system ($1,995.75). You could argue that the high cost of the exhaust and driveline are the result of all that power, so we can live with this choice.
In the "Captain Obvious" department, we have expenses like motor mounts, air filter, engine oil, starter, fuel system, and cooling system. We took a simpler-is-better approach here, looking for parts that were reliable enough to run hard on the street, but weren't overly complicated or outrageously expensive.
We also learned that it helps to be really close to the parts store. We lost track of how many times we ran to the AutoZone for stupid, obvious stuff, like hose clamps, a throttle bracket, or some header bolts. It seemed like as soon as we got back from the store, we needed to go right back again. (Feel free to use our cost chart as a check list.) We learned a ton doing this swap, like how to set up a Barry Grant Mighty Demon and tweak the idle circuit. We learned how to build a cool shifter pedestal, and what's needed for a better breather system that won't puke oil on your headers. In fact, this huge exercise is going to be the basis for many more cool stories we're going to do later on.
We also want to thank Tim Lee of Don Lee Auto in Rancho Cucamonga, California, for letting us invade his shop for a week. Tim has the patience of Job, and knows how to do just about anything and where to find everything, like our fuel system stuff. When it was finally completed, the 496 fired right up with no problems. The Stainless Works headers and exhaust make kids wreck their bikes from blocks away. No need for a horn or a stereo, thank you.
Yuck! This is the mid-'70s...
Yuck! This is the mid-'70s big-block truck engine that came with the '68 Chevelle.
Since then, we've put about 1,500 miles on the Howitzer big-block. The Chevelle gets about 8 mpg, but has insane power to make up for it. With the exception of an early rich condition that was remedied by a jet change, it starts, idles, and lays rubber like a champ. With a 110-mile round-trip commute, we've experienced highway miles, city driving, and blood-boiling traffic jams. In one instance, outside temps neared 100 degrees, and the temp gauge stayed solid on 190 degrees while idling for over an hour. After a few more items on the punch list, like safety stuff, steering components, some chassis dyno tuning, and gauges, we'll be ready to swap the slicks and hit the track. Next month, we'll show you how we made our own breather system, and cured a bunch of oil leaks.
The Reliable Ones
TCI officially rates its Super StreetFighter transmissions to 600 hp, but they confided to us that's to cover the Ford version, which is weaker due to the Ford's design. The Turbo 400 is good for 700 hp, and features both automatic and manual shifting. The Super StreetFighter features Alto Red Eagle clutches, Kolene-treated steels, extra-wide Red Eagle-lined bands, large-diameter servo assemblies, improved lubrication, new sprags/roller clutches, higher line pressure, and increased thrust capacity. The 10-inch Super StreetFighter converter is designed for big street cams like ours (280 to 310 degrees duration) and gear ratios between 3.73 and 4.88 (we've got 3.70s). Its stall speed with a big-block is rated between 3,800 and 4,000 rpm. Our Super StreetFighter converter also has anti-ballooning plates, a hardened pump hub, and furnace-brazed fins. Rounding out the trans package is a TCI Outlaw shifter, trans cooler, and flexplate.
After yanking the truck lump, the HVAC box was tossed, the bay was cleaned, two cans of Dupli-Color semi-gloss went on, and some new wire loom went over the harness. The Howitzer bolted right up to some new AutoZone motor mounts. The Jeg's aluminum radiator fit perfectly and was a sweet buy at just $299.99. Oh what a difference a day makes.
An Ant's Eye View
From below, the magnitude of our upgrades can be fully understood. The CPP control arms were pre-existing, but it's important to note that we originally installed the uppers with the shaft bolts reversed, so that the bolt heads face the engine. We knew this would provide important header clearance months ago. The Meziere starter was a late addition; another brand was tried (twice), and failed after a few initial starts. Not so with the Meziere TS100, which has performed flawlessly cold and in heat-soak. The most obvious thing in this shot is the Stainless Works X-pipe, which works a ton better than a traditional H-pipe. The idea behind the X-pipe is that regardless of which collector presents the flow pulse at the junction, the gas flow has equal access to both 3-inch pipes.
With the Stainless Works long-tube...
With the Stainless Works long-tube headers mounted on the big-block, we discovered that the "ears" on a Turbo 400 interfere with the headers.
The Turbo 400 is longer than...
The Turbo 400 is longer than the old Turbo 350, but even if it wasn't, we wouldn't want to use the stock steel driveshaft to transmit 635 lb-ft of torque.
Pulling out the HVAC brick...
Pulling out the HVAC brick from the passenger side made a big difference.
Down below, the stock trans...
Down below, the stock trans crossmember was retained for the longer TCI Turbo 400.
Just as we were gathering...
Just as we were gathering parts for the swap, Edelbrock came out with its Victor Series billet aluminum fuel pump and regulator.
Rather than order a bunch...
Rather than order a bunch of AN fittings by mail, wait for them, then hope they're right, we went local.
Most big-block Chevelle headers...
Most big-block Chevelle headers on the market have clearance issues with the steering shaft, and our 1 7/8-inch Stainless Works headers were no different.
This cool shot shows the TCI...
This cool shot shows the TCI trans cooler mounted to the Jeg's radiator.
Our Chevelle had no coolant...
Our Chevelle had no coolant overflow when we bought it, so we had to buy a new one from Summit for $23.99.
The Stainless Works headers...
The Stainless Works headers and dual exhaust were incredibly well made, and had every bolt, clamp, and bracket, as you would expect from a premium-priced product.
This angle shows the entire...
This angle shows the entire Stainless Works exhaust system. Even at 3 inches in diameter, it cleared our nominally larger Currie 9-inch rear, a larger-diameter 3.5-inch Inland Empire driveshaft, and the Air Lift bag shields (they protect the air lines from heat on the CPP springs).
You think we're gonna spend...
You think we're gonna spend $7,500 on an engine, and not put the best oil in it? Pennzoil Platinum is a full synthetic with an API service rating of SM/CF, and is available in 0W-20, 5W-20, 5W-30, 10W-30, 5W-50, and 15W-50 weight.
Here's the finished engine...
Here's the finished engine bay. We reused the alternator, power steering pump, and original engine dress. The K&N Xstream filter with 3-inch drop base was a late addition to the mix, but worth the $125.99.