Words And Photos: Richard Holdener

Who makes a better big block, Ford or Chevy? Asking that question around Ford and Chevy fans is like bringing up religion or politics at the Thanksgiving dinner table. Like a turkey fresh out of the oven, no matter what side of that argument you might be on, the discussion is likely to get plenty heated! That two sides exist is reason enough to plan some sort of comparison, to say nothing of the fact that it gave us yet another reason to visit our local LKQ Pick a Part deli for some fresh meat (a.k.a. new dyno mules)!

In reality, our grand plan had three initial parts. Part one was the trip to the yard followed by the selection of two big-block test motors (one Ford and one Chevy), then, finish up strong by tossing them on the dyno to see which one makes more power. Plans are much easier on paper, but the harsh reality of the yard meant we had to choose not just from the vast array of available years and factory power levels, but the availability at hand (on a sale weekend no less). Pickins’ were slim but we managed to come up with a suitable pair of big blocks for our test, and on a sale weekend that slash 40% of the price.

Rather than hope against hope for a Police Interceptor or LS6, we set our sights a little lower and chose from the plethora of pedestrian power plants located in the engine bays of full-sized trucks. Though Chevy offered a more powerful, injected Gen VI version from 1996-99, we chose the previous (and more abundant) Gen V TBI 454. Rated at 230 hp (or 255 in the SS) and 385 lb-ft of torque, the TBI motor was hardly legendary in its performance, but it was the workhorse of the gas family and offered both plenty of torque and (more importantly) future potential. Likewise for the Ford 460, as we steered clear of the later EFI version, choosing the earlier carbureted version instead. The injected 460s have a reputation of weak cylinder heads, we were planning on running carburetion any way and the yard was full of both, so it was factory carburetion for the Ford. The stock 1986 4-barrel 460 was rated at 245 hp and 385 lb-ft, putting it 15 hp above the Chevy 454 while matching the torque output. On paper, the 1986 460 and 1993 454 seemed to be a good match up.

For Part 1, the goal was simply to get the motors and run them on the dyno to see if we had a couple of players. You never know for sure what you are going to get when you yank one from the yard, but luck was with us and we got a couple of runners (or rather walkers judging by the less than amazing stock horsepower levels). For dyno use, we had to make a few changes to each of the motors, but most of the changes occurred on the 454 Chevy. Off came the TBI injection and computer-controlled distributor to be replaced by a dual-plane, Weiand Stealth intake and MSD.

We planned on running a similar intake on the Ford but our loaner (from a fellow Ford enthusiast) did not arrive in time for the test (some friend!). This forced us to run the factory cast-iron intake on the 460, which immediately put the Chevy at an advantage. Fear not as we will rectify that situation in Part 2 when the big blocks receive mild (RV/towing) camshafts and a valve spring upgrade. Both motors were run sans accessories (electric water pump), with long-tube headers and with air/fuel and timing maximized for power production on the 91-octane pump gas.

The first big block on the pump was the 7.5L, 460 Ford. Greasy from an obvious oil leak, the first of the two wrecking yard warriors was nonetheless ready for action. We installed the 750 HP Holley used on both motors and tuned the air/fuel mixture to a precise 13.0:1 (though we tested richer air/fuel ratios to see if that held any additional magic). After dialing in the air/fuel and timing, the 460 responded with plenty of torque but somewhat lackluster peak horsepower numbers. The 7.5L thumped out over 400 lb-ft down below 2,000 rpm (perfect for towing), while managing peaks of 299 hp and 439 lb-ft of torque.

These numbers didn’t look bad compared to the factory rating of 245 hp and 385 lb-ft until we saw how well the Chevy performed. Run in a similar configuration (headers, Holley and Weiand), the 454 Chevy produced 332 hp and 447 lb-ft of torque. The Ford offered more torque up to 3,000 rpm, but the Chevy pulled ahead above that point. How much of that was the intake and how much was simply neglect or excessive mileage we can’t say, but the intake situation will be rectified in Part 2 before we add a cam upgrade to the mix. After that, we plan on aluminum heads, wilder cam timing and even some nitrous. Heck we might go hog wild and add boost or super size these behemoths, but for now let’s call it a tentative Chevy 1, Ford 0 until we officially install the intake in Part 2.

Despite the big bore and short stroke (relative to Chevy), the 460 Ford is best known for torque production and we can see why. Even on this low-compression, 1986 version, torque production exceeded 400 lb-ft from (below) 2,000 rpm to almost 4,000 rpm. The mild cam ensured that the torque party never translated to any serious horsepower production, but the combination was perfect for heavy hauling and will make an excellent starting point for any performance build up.  We expected more power from the 460 given that it was rated 15 hp higher than the Chevy in stock trim, but on this day and on this dyno, the 460 produced peak numbers of 299 hp at 4,300 rpm and 439 lb-ft of torque at 3,000 rpm. Was it age, mileage, or the lack of an after market intake that kept the 460 from bettering the 454? Look for part of that answer in Part 2.

At lower engine speeds, the 460 actually out performed the 454 but above 3,000 rpm, the 7.4L Chevy came alive. Some might be quick to credit the Weiand intake manifold for the extra top-end (if 4,700 rpm can be called top end) power, but whatever the reason, the Chevy made more peak power and torque than the Ford. Run with the Weiand intake, Holley carb and MSD distributor, the 1993 454 produced 332 hp at 4,300 rpm and 447 lb-ft of torque at 3,500 rpm. The Ford guys can complain all they want, but chalk up round 1 for the Chevy guys!

Read PART 2 now! 

Sources

Holley/Hooker/Weiand
holley.com

Lucas Oil
lucasoil.com

MSD
msdignition.com

LKQ-Pic a Part
lkqcorp.com