NHRA Chassis Certification - Performance Q & A

Kevin McClelland Feb 15, 2010 0 Comment(s)

Emissions Camino
I am putting a ZZ4 H.O. 350 in my '86 El Camino and have two concerns. First is the ignition. My El Camino has the original four-wire HEI distributor and associated computer in the passenger-side kick pad. I think I'd like to retain the computer and smog stuff to keep it legal in California. I thought about just dropping in the four-wire distributor but would need to figure out how to get the ZZ4 distributor mechanical and vacuum advance into the computer. Do you have any suggestions? The vacuum advance of the ZZ4 will pose a clearance challenge if I use the ZZ4 HEI distributor.

My second concern is the existing exhaust system, cast-iron manifolds piped into single exhaust with an air-injected cat converter. I don't know of anyone who makes headers that would be temperature and mechanically friendly to the air pump, A/C, and lots of other little wired sensors, so I'm leaning toward keeping the cast-iron manifolds and going to dual exhaust with a small cat converter on each pipe before the muffler(s). Any thoughts or suggestions?

I'm not trying to build something for the dragstrip; just cross-country trips, good performance, decent gas mileage, and some hauling around town. I currently get 15-21 mpg with the 305 V-8 holding it down at 70 mph and just want something a bit stronger. I put a ZZ3 in my '65 El Camino and loved it. The rest of the package was a TH350, A/C, P/S, disc brakes, HD suspension, and 14x7 rally wheels, and I just enjoyed running hard through the curves and having people wonder what was going on. A moving van creamed me and the '65 some years back, otherwise I'd still be driving it.

I look forward to any suggestions you might share with me. I am a little busy working and going through chemo in Houston this year. Thanks and regards.
Brad Stone
Los Angeles, CA

Hearing about your '65 getting wasted by a moving van breaks our heart. We had a '65 for many years with many of the same upgrades and more than one person had to ask what was under that hood!

Back in the early '90s GM created the H.O. Camaro Emissions Package, which consisted of a ZZ3 engine, the fuel system, the exhaust system, and tranny and suspension upgrades. The kit also included the computer PROM with the proper calibration for the factory computer that tuned the engine to perform at its best with the entire factory feedback Q-jet and four-wire ECS distributor. The beauty of this package is that it produced 308 hp, emissions legal, through the factory cast-iron manifolds, single high-flow cat, and dual-snorkel air cleaner. You can replicate this package with some minor tweaks that will pass California's emissions regulations-and push the horsepower up around the 325 mark.

Let's start with the exhaust. Edelbrock offers a complete TES (tubular exhaust system) for the '83-88 Monte Carlos, Malibus, and El Caminos. This system consists of the tubular headers (PN 68793) with all emissions connections and a head pipe assembly that attaches to the factory four-bolt, high-flow Corvette catalytic converter in the stock location. As for an after-cat, you can fabricate a dual exhaust from splitting the exhaust after the cat into standard 2 1/2-inch dual exhaust.

Contact Tom Woodside at GMCOPO. He was one of the engineers on the Camaro project for GM from the beginning. He has a stash of the PROMs for the factory computer and firsthand knowledge of the modifications necessary to make your El Camino a really clean runner. You can reach Tom at 248.275.5828. He really enjoyed this project and wants to see as many on the road as possible.
Sources: edelbrock.com, gmcopo.com

Technical questions for Kevin McClelland can be sent to him at chevyhi@sorc.com.


Connect With Us

Get Latest News and Articles. Newsletter Sign Up

subscribe to the magazine

get digital get print