Who did it best back in the late-1980s and early 1990s, the 5.0L Ford or TPI Chevy?
OK, fellow travelers, let’s crank up the DeLorean to 88 mph and venture back in time to the start of the modern muscle-car era. Some may not remember, but there was a time when production cars weren’t running around with 400, 500, or even 600 hp, to say nothing of 700-plus-horsepower Hellcats! Back when Billy Idol was dancing with himself and Cindy Lauper just wanted to have fun, the power outputs of the hottest Camaros and Mustangs were literally half of what they are today. The ponycars wars were still being waged, but many carbureted fans thought the introduction of (then-new) modern fuel injection would surely spell the end of performance. History has shown those doomsday predictions not only to be unfounded, but that the reverse was actually true. The injected 5.0L H.O. Mustang and TPI Camaro were the performance predecessors of the killer Coyotes and Z/28s we have today. To show our respects to all things 1980s (and early 1990s), we had a shootout between a 5.0L H.O. 302 and an LB9 TPI 305. We’d then use these humble beginnings to illustrate how to bring them up to the current level of performance, if such a thing is even possible.
Looking through the years, we see Chevy’s LB9 TPI 305 was first offered in 1985 as a replacement for the LU5 Crossfire engine. The LB9 shared most of the carbureted L69 H.O. engine’s components, but the difference was the unique, long-runner EFI induction system. The lengthy intake runners produced a massive amount of torque, but limited power production at higher engine speeds, especially on the larger L98 350 engine. From 1985–1992, the LB9 was offered in outputs ranging from 190 up to 230 hp, and as much as 300 lb-ft of torque, with the major differences being cam profile and exhaust configuration. The specs on the original cam profiles used for the LB9 varied by as much as 0.065-inch lift and 27 degrees, but this mattered little to us, as we plan to replace the factory cam ASAP. As luck would have it, Westech had an iron-headed LB9 305 stuck under a shelving unit. Apparently, it was not one of the shop’s most popular test engines, but we were excited about scoring such a pristine TPI 305.
By contrast, the 5.0L Ford 302 was rated at 225 hp and 300 lb-ft of torque through most of its run in EFI configuration from 1987–1993. Fuel injection actually first appeared in 1986 with the one-year-only, 200hp version of the engine. The 5.0L continued in the 1994–1995 Mustangs with a slightly revised induction system, but despite being re-rated by Ford down to 205 hp in 1992, every 5.0 we have ever tested made the same power. Though both the Chevy and Ford displaced 5.0L, they did so with dramatically different bore and stroke specs. The 302 Ford combined a 4.0-inch bore with a 3.0-inch stroke. This compares to a 3.736-inch bore and longer 3.48-inch stroke for the 305. The 305 Chevy is often chastised for its small bore, but under the operating conditions the stock engines were intended to run, the bigger bore is of little benefit. That may change once we start the modifications, but for now, the fact that both engines produced nearly identical power shows there is more than one way to skin the proverbial performance cat.
Our good pal, Mark Sanchez, found our test engine, which was part of a recent take-out that included the complete T5 five-speed transmission. You can also find 5.0 engines in fullsize trucks, Thunderbird and Mercury Cougar, or a GT-40-equipped Explorer. Though Ford dropped the 5.0L in favor of the Modular engine in the 1996 Mustang, it continued to use the little Windsor in the Explorer through 2001. With the exception of the T-bird, all of these applications would offer slightly different 5.0L configurations, but would all provide a solid foundation for any 302 buildup. While 1994–1995 H.O. motors offered a revised intake (and larger throttle-body) to fit under the hood of the new platform, there was little (if any) change in power.
To establish our baseline, we configured each engine for dyno use. Off came all of the accessories, while the induction system was stripped away to the bare throttle-body. Since we employed a stand-alone Holley HP management system, it was unnecessary to use the MAF and associated intake tubing. We found that the stock injectors in both of these high-mileage engines were long since clogged, but the stock Ford injectors cleaned right up. We replaced the stock TPI injectors with a set from a Gen VI 454 truck. We ran both engines with a Meziere electric water pump and 1-3/4-inch long-tube headers. Both of the factory combinations were run with the same air/fuel ratio (12.9:1) and each received the timing value that maximized the power output on the 91-octane pump gas. Additionally, both engines received new MSD distributors, because neither of them would be run with their respective factory ECUs.
First up on the dyno was the 5.0L Ford. Run with the diminutive, stock throttle-body feeding the H.O. upper and lower intake, the 302 produced peak numbers of 261 hp at 5,100 rpm and 322 lb-ft of torque at 3,500 rpm. Though the big bore and short stroke suggested a high-rpm combination (like its cousin, the Boss 302), the 5.0L Ford excelled much more at low-speed power and torque production. Note that the peak power occurred at just 5,100 rpm. The long-stroke Chevy followed suit with peak numbers of 267 hp at 4,600 rpm and a slightly higher 332 lb-ft of torque at 3,700 rpm. Like the Ford, the Chevy was run with long-tube headers that helped power production, but since both combinations were run in identical trim, the relative power numbers were accurate and comparable. Given their original ratings, it’s not surprising the two offered near identical power outputs, with the differences being a function of the amount of mileage logged by each over the years. Check back with us next time to see how your favorite 1980s muscle motor responded to the first round of modifications.
5.0L Fist Fight: 302 Ford vs. 305 Chevy
Run in stock trim with unknown mileage, the two competitors offered surprisingly similar power curves and peaks. The Ford produced 261 hp and 322 lb-ft of torque, but the Chevy countered with 267 hp and 332 lb-ft of torque. Given the near-identical original power ratings, we suspect the condition (and mileage) of the engines had more to do with the results than things like bore and stroke. With our baseline numbers established, look for some 5.0L mods on the next test.
The post 302 Ford vs. 305 Chevy! Part 1: Intro and Baseline appeared first on Hot Rod Network.
Source: Hot Rod
23 total views, 1 today