About ten seconds after we announced the GMHTP/Kenny Brown Driving School at Virginia International Raceway, we realized that our resident road racer-project car Thunderchicken-was far from ready to participate. The car had been used for everything: a daily 100-mile commute, drag racing, road racing, autocrossing, school bus, you name it. In the process TC had accumulated a backlog of minor ailments which needed to be addressed. As of this writing, over 40,000 miles has been put on our Motorsport Technologies-built 396 LT1 and it was due for some routine maintenance. The chassis and suspension were not immune from deterioration either; wear problems in our continually cantankerous KTRE 12-bolt required, at the bare minimum, a new lube fill with synthetic, and the passenger-side wheel bearing was showing just a bit too much play in it for high-speed road racing.
We were also experiencing a high-rpm miss and dyno results were showing TC down about 30 rearwheel horsepower from its original condition. As with most aging LT1s, the ignition system is always under suspicion, and since our Opti-spark was just changed, it was a good bet that the plugs and wires were responsible to some extent. To that end, we ordered a set of ACCEL Extreme 9000 wires and U-groove plugs. Some popping on decel also raised concern about the status of the valvesprings, and with a .547-inch lift cam and so many miles, it was decided to replace the original worn-out valvesprings with units from Comp Cams (part No. 977-16). These valvesprings are the same ones that MTI puts in all its 396 street strokers and are oversized for the larger spring pockets cut into the heads by MTI.
Entrusting our MTI 396 to the folks at Strope Speed Shop in Washington, Pa., however, was not a hard decision. Strope has shown us over and over that they can handle any curve ball we throw. Additionally, they have plenty experience working on road-raced GMs, so they had first-hand knowledge of TC's intended use. Upon hearing that we planned on changing the valvesprings, Strope decided to drop the engine, transmission and front K-member out from the bottom, in the same manner the factory originally installed it. Many F-body tuners are split in their feelings on how an LT1 or an LS1 should be removed from an F-body; we've seen it done both ways with success. One compelling reason to pull the powertrain rather than swap the valvesprings in the car was that Strope also wanted to change the plugs and wires and perform a cylinder leak-down test in every hole. The total time it took to remove and install the powertrain (some four and a half hours total) was offset by the time saved doing these other tasks. It also allowed some much needed cleaning in the engine bay and some tidying of wire harnesses.
While the valvesprings were being changed, it was noted that several of the lifters were weak and one pushrod was bent. (Oops! Missed a few powershifts and over-revved it a dozen or so too many times...) Also the timing chain was noticeably sloppy and there was 13 percent leak-down in all the cylinders. We dished out a healthy beating to our MTI 396, so the wear we discovered should be considered excellent for such a serious stroker engine with so much hard use (i.e., abuse!) over such a long time. We have been extremely happy with our MTI 396, and with new springs we think another 20,000 miles is not out of the question. Perhaps next spring we will plan a full freshening with new lifters, rings, timing chain, valvesprings and bearings, but for now we've got a clean bill of health. Our main concern going into VIR was not the powertrain, but keeping it out of the wall!