Should you really get energetic, you can change out other pods and gain an oil pressure and water temperature gauge as well. Just don't forget to swap in the proper sending units on the engine for water temp and oil pressure. You can retain your old speedometer if you so desire, even though the font on the face is a little different than that of a Rally gauge cluster speedo.
I did a step-by-step how-to in a '66 a few years ago, so it's not too hard to do. You may even want to take it to the next level and add a clock in the empty hole and install a hood tach. Hood tachs are also available as reproductions. The clock, however, is not reproduced at this time (no pun intended). You can find one on eBay or call Ron Johnson from Potomac Pontiac at (301) 668-0101. He has used clocks available from time to time (there it is again).
I have not seen block-off plates available from any of the aftermarket Pontiac parts houses. It's funny-most people add gauges, not delete them. Maybe that is why no one makes the block-off plate.
What About The L78 Block?The buildsheet accompanying my '79 T/A 400 four-speed indicates a W72 "Performance Package" option and an L78 400 engine option. An article appearing in the Aug. '04 issue of HPP about 10th Anniversary Firebirds refers to L78 engines. When Paul Spotts was recently discussing W72 engines, could he have meant this L78 400 engine? He seems to suggest that perhaps the W72 package actually included an engine with a stronger block.
I'm guessing that I am not the only '79 Firebird owner who is curious as to whether W72 and L78 designate different 400 engines. Are all '79 400 engines the same? Alternately, are 400 engines installed in '79 Firebirds capable of surviving high-performance re-builds, say a 6,000-rev limit? Or as Jim Hand states in his book, How to Build Max Performance Pontiac V8s, are all 400 engines built since 1975 poor cousins to the original line and not sufficiently strong (thin main webs and cylinder walls) to withstand high-performance use? Thank you so much.Andy HessConfused in Spokane
Rocky Rotella responds:As a result of my ongoing Pontiac research, I was asked by Jim Hand to assist in providing technical information for his book during its preparation in 2003. The information he initially published was current and even cutting-edge. Being an active researcher in the hobby with heavy focus on the '70s, I can tell you the painstaking efforts of a small group of highly-dedicated hobbyists has recently unraveled many of Pontiac's mid-to-late '70s mysteries, and the No. XX 481988 block falls into this category.
We knew that Pontiac introduced a series of revised 400ci-block castings during the mid-'70s that included casting Nos. 500557 and XX 481988. We also knew that Pontiac engineers eliminated the harmonic balancer from the nose of the crankshaft. I later spoke with a Pontiac engineer who confirmed that the elimination was a direct attempt at reducing overall vehicle weight to increase fuel economy, and that material was removed from both the block and crankshaft to lighten them, too. A detailed article entitled, "A Question of Balance," in the May '04 issue of HPP covers this very subject.
Having seen a number of disassembled No. 500557 engines, I am confident that when compared to previous 400ci castings, the No. 500557 definitely contains narrowed main saddles and oil pan rails, and-though not readily apparent-thinner cylinder walls. It's these features that make blocks of this vintage less desirable for high-horsepower builds. That doesn't, however, suggest that every Pontiac with a No. 500557 block under its hood can't be built to make power or that it is a ticking time bomb!