by Darr Hawthorne
6/7/04

ometimes when you are busy your hot rod takes a back seat. With the beginning of the new drag racing season, both my son Zak and I have been hard-pressed to get onto the next phase of improvements to DRO’s Project Street FX Altered Wheelbase Chevy II debuted in the January 2004 issue.

This first upgrade was to battle a weakness we had found with cooling the 468-inch Chevrolet big block engine. While we’d installed a new 4-core radiator and separate oil cooler from the beginning, often the water temperature rose to 215 degrees and a couple of times hit 225 or 230. There are no inner fender wells on this car and to keep the 60’s A/FX look we felt that a traditional fan shroud wasn’t very interesting either. The fan had already been changed over to a 17 inch, six-blade Flex-a-Lite unit, which helped air flow a little, so we needed to find other solutions to this nagging overheating issue.

Since the engine used a stock, steel Chevrolet big block “long” water pump, with unknown miles, this seemed like a good place to start. After reading up on all of the aluminum aftermarket pumps, we found that Milodon made a pump that would move more coolant with a claimed horsepower increase. However, none of these units were available from Jeg’s, Summit, or the local speed shops, so our other choice was Weiand’s Action Plus model 925-8242 pump which we found in stock at Jeg’s. This Weiand aluminum water pump sports a 5/8-inch heavy-duty shaft and 6-blade anti-cavitation impeller, claiming optimum flow rate while using less power.

When speaking recently with Kevin McClelland at Flowmaster, he recommended trying a set of their new Flowmaster Super 40 3-inch mufflers.

Reportedly the tone of these new mufflers was going to be deeper, interior noise would be reduced, they would make more horsepower and somehow the newly designed muffler made the engine run cooler. With this combination of mufflers and high volume water pump, it seemed that we might have the winning ticket to reduce the big block’s heat while cruising to Bob’s Big Boy on a hot summer night.

The change-out of the water pump took about 90 minutes, but a side trip to the nearby Auto Zone found the gaskets we needed, somehow they were not included with the pump shipped from Jeg’s. It was a simple installation and the fit was perfect.

Just about anyone with a stout cam and headers driving on the street knows of your engine exhaust noise ability to set off the alarm on a parked vehicle as you drive by. Since we’d been driving the car on the street, we developed a game to play on the way to local events called Alarm Golf. When driving on city streets the low-end muffled noise would set off car alarms, sometimes just a brief blip and the alarm resets: -one point, but if we could fully engage an car alarm: -three points.

The car headed to Magic Muffler, a Van Nuys Boulevard staple for almost 50 years where thousands of hot rodders have had their welding, header, muffler and exhaust leaks fixed. The mufflers already in place were also Flowmaster, but had been purchased in 2002 so we’d have a frame of reference for any difference in sound levels. Interior sound levels in the Chevy II had been high with these mufflers, so a change would be good.

It was another simple installation by the veterans at Magic Muffler, but now we had a full 3-inch inlet and exit with the new Flowmaster Super 40’s. On the drive back home there was a noticeable change inside the car; we could actually hear each other talk.

I asked Flowmaster’s Kevin McClelland why the Super 40 units were so different. Kevin explained that the new unit has redesigned interior chambers to reflect and cancel sound while retaining the low-end rumble most hot rodders desire.

Heat is reduced because the muffler removes backpressure and the relief of backpressure scavenges heat out of the combustion chamber providing a cleaner charge in the cylinder to fire the next combustion cycle within the chamber.

Then we were off to the dragstrip, where in practical terms the engine constantly ran cooler with the Weiand Pump and Super 40’s combination. There was no appreciable change in elapsed times through the mufflers, but the sound was solid and deep down the Irwindale Drag Strip 1/8 mile. Street driving is also better with the reduction in operating temperature now eight to 12 degrees less with the addition of the new Weiand Pump and Flowmaster Mufflers.

OK, but would the new mufflers still set off parked car alarms? Yes they do and Alarm Golf is still alive!

The next phase of Project Street FX will be all horsepower with the addition of a tunnel ram and dual quads, aluminum heads, roller cam, headers and some dyno time at JMS Machine in Monrovia, Calif. Stay tuned.

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