February 2013 Chevy High Performance Q&A

Kevin McClelland Mar 6, 2013 0 Comment(s)
1302chp 02 O  Chevy High Performance Q A 1/2

Back in the Day!

When we sometimes refer to the way it was “back in the day”, we often remember things better than they actually were. We polish up the past for our memories. But in some cases it really was that good.

This past weekend I had one of those moments that truly was a great time in the performance aftermarket. My wife, Lisa, and I took an R&R three-day weekend in Las Vegas. When we were on our way up, I remembered that my good friend Les Figueroa had moved his business Figspeed from Lake Havasu up to Henderson, Nevada, a little over a year ago. Figueroa has operated Figspeed for many years as trackside racer support with a full trailer of performance parts to keep the racer going down the track. He and his team come to most PSCA, NMCA, and NHRA divisional events, in Division 6 and 7 out here on the Left Coast. When he moved his performance operation up to Henderson, he set up his shop to support racers with a complete speed shop. Now, I don’t know how many of the youngsters out there ever visited a local speed shop, but back in the day, this is where we learned about the latest and greatest performance offerings and could order them for our builds. There was no Internet. There wasn’t Jegs or Summit. There was, of course, the J.C. Whitney mail-order catalog, which would carry some of the good performance stuff, but the speed shop was where you could hang out with your gearhead buddies and pick the brain of the counterman. The counterman was usually one of the top racers at your local track and was pretty hip on the latest performance parts.

When my family moved to Southern California back in 1971, the killer speed shop in our area was Glendale Speed Center. My dad and I would frequent this haunt for gaskets, hardware, and parts when we were assembling our Fiat Altered car, powered by an injected big-block.

Walking into Figueroa’s place was like I was stepping back in time 40 years ago. The store is filled with the latest tricks from ARP, ATI, B&M, Holley, Jesel, Milodon, Moroso, MSD, Strange, and many more performance companies just waiting to offer instant gratification. Check out the shop at figspeed.com. Yes, our days of Jegs, Summit, and even Amazon are great, but sometimes you do get stuck and need that one part to get your project going. This is one of the things your local speed shop is great for. Also, again as back in the day, most of the people working in these shops were racers themselves and could steer you right to the parts you need, the first time.

There will always be the online deals, but sometimes you can’t beat the face-to-face transaction of building speed. Search out your local speed shop and support them in every way you can. It will bring you back to a time in our history that we need to cherish.

Trans-Am Racer

My ’69 Z/28 is patterned after a Trans-Am car of the era, as I have watched them race in person and have always enjoyed them. I built the car with a NOM 383, a COMP XE268H hydraulic cam, a Performer RPM Air-Gap, and aluminum heads to have a broad torque curve and good street behavior. That it has in spades, up to about 6,200 rpm, but now I’m interested in a higher-revving combination more in character with the original 302 but with (of course) more horsepower and torque.

I am considering a 377 (4.155x3.47) or a 427 (4.125x4), as it seems the new generation of hydraulic roller cams rev to 7,000 easily and that would suit me fine. In addition, I have wanted a cross-ram (yes, I know they are expensive) to go with it but am concerned about streetability and performance, as no one ever seems to use them. I must admit, I really only prefer the cross-ram for appearances unless there is a sound performance gain that can be achieved. As a follower of your column, I will pay close attention to your advice. Thank you.

Tom Purtill

Richmond, TX

Your 383 sounds like a perfect combination that gives you trouble-free enjoyment. Stepping into a new, higher-revving combination will give away some of your street manners. If you go with the large-displacement 427 you’ll get the bump in horsepower and torque you’re looking for. Pushing that combination to 7,000 rpm could be a challenge unless it’s a true race-type build. Our vote is for the large bore with the relatively short-stroke 377. These engines have always had a soft spot in our heart as they would rev quickly and make great power with that large bore for breathing.

You reference the revving potential of the hydraulic rollers. One of the issues with a complete hydraulic roller setup is the valvetrain mass. Keeping this under control at 7,000 rpm could be challenging. If you decide to go this route, please work with your camshaft supplier of choice and communicate your goals. You’ll want to keep the valves, springs, and retainers as light as possible, as they are the hardest to control. If this is your weekend warrior, look into a high-quality mechanical roller setup. Small-block engines don’t have the lifter wear issues like the big-block engines. Also, if you went with the Isky EZ-Roll lifters you wouldn’t have to worry about it at all. Opening up the valve events to a mechanical roller design will give you the limiting speed you’re looking for with no issues.

Now, back to your desire to use a cross-ram intake manifold. GM did offer these manifolds in the trunks of the Z/28s, as they wouldn’t come from the factory installed. This intake system was sold as an option, but the only problem is that it was installed in the wrong end of the car. These manifolds look very cool, but they are also very challenging to get to perform well. They have mixture distribution issues at slow engine speeds. They will puddle fuel in the manifold between the runners and in voids in the plenum, which would lead to bad habits at idle and part throttle. Once the engine was at full song, they would run well, but they don’t perform better than a single four-barrel, single-plane manifold setup. Yes, the long runner lengths do boost the torque at slower speeds, but rarely were they fueled correctly at these speeds. Several aftermarket suppliers released their own version of the cross-ram with some success of improving the distribution issues. These manifolds still couldn’t keep up with the current offerings of single-plane performance.

Keep us posted on your progress for power. We’d be very interested to see the finished product and what you decided to go with. Good luck, and long live the high-revving small-block.

Sources: compcams.com, iskycams.com

There She Blows!

My son and I installed a freshly rebuilt 0.030-inch-over 350 engine in his ’78 Camaro. He ran it for about a week and he noticed that one of his lifters kept tapping. He removed the valve cover and adjusted the rocker arms, but in a day or so it would return. Upon removal of the valve cover, he noticed that a couple of the studs in the heads seemed to be pulling out. That’s when we decided to change the heads.

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