Modified Mustangs & Fords
Y-Block Engine Build
Ted Eaton takes his 375-inch Ford "Y" to the Engine Masters Challenge and changes perception of this Cold War classic
Ford Division's first overhead valve V-8, the Y-Block, remains one of the sexiest V-8 engines ever with its perfect symmetry, finned and studded Thunderbird Special valve covers, dual-plane "stacked port" manifold, and 45-degree-cocked ignition in the backyard. Because it has 16 solid tappets thrashing out a sweet beat, it yields the aura of traditional American V-8 power. When you marry one of these engines to the chassis of a vintage Thunderbird or shoebox Ford, it takes on the life of an era one-half century gone.
Ford introduced the 239ci Y-block in 1954 in Fords, and a 256ci version in Mercurys to replace its flathead V-8 introduced in 1932. The Y-Block swiftly grew to 272, 292, and finally 312 ci by 1956. Though the Y-block was revolutionary when it was introduced, it was cursed with limitations right from the start, mostly in the area of displacement and cylinder head design. You couldn't fit a lot of displacement in it and cylinder head design has never been a strong suit for Ford. There's only so much you can do with this engine if you have limited budget and resources. If you have the talent, resources, and capital, however, you can make real power with this engine.
Professional engine builders like Ted Eaton and John Mummert are passionate about the Y-block and have been working with this engine for decades, determined to make previously unheard of amounts of power. However, it has never been easy. John Mummert of San Diego, California, is well known and respected for his Y-block efforts, which include producing cool aluminum cylinder heads and induction systems for these venerable Ford V-8s. Ted Eaton, more than a thousand miles away in Lorena, Texas, is every bit Mummert's equal in that he knows the Y-block like few others. This is where West Coast and American heartland get together to rock the firmament.
Y-Block vs America's Best
Ted Eaton of Eaton Balancing boldly decided to enter Ford's Y-block in the Engine Masters Challenge at the University of Northwestern Ohio. "For the '07-'08 Engine Masters competitions, I built a 312 with 0.022-inch overbore and a stock stroke to get 316 ci. For 2009, there were major rule changes. Significant was increasing the rpm range in these dyno pulls with compression as high as 11.5:1," Eaton comments. "Although the 316 looked to be very good, especially at 2,500-6,500 rpm, the rules would place this Y-block much lower in the field simply due to the allowance of a roller camshaft thrown into the fray, and increasing rpm to 3,000-7,000 rpm in the rest range." He went on to say, "I was already at a disadvantage by having to use stock iron heads given these guidelines."
Eaton concluded his 316 was not suitable for competition in 2009, which is when he decided to go for displacement and a fresh approach.
"My original plan for this engine was a 4.000-inch bore and stroke to get 403ci. This combination probably would not have given the best overall score, but would have given us impressive peak power numbers," Eaton explained. The 4.000-x4.000-inch bore and stroke combination created water problems when he went wide open throttle at low rpm under load on the dyno. Investigative efforts showed he could not get there with this bore and stroke combo without coolant issues. He had to compromise.
Eaton opted for a 3.859-inch bore coupled with a 4.000-inch stroke to achieve 375ci along with more cylinder wall thickness from a B9AE-F 292 non-steam hole block. Eaton told us that while the 3.700- and 3.800-inch strokes had been tried successfully with Y-blocks, he wanted to know how 4.000-inches of stroke would work in a Y-block. Would it fit and would it make power without breaking?
Eaton began with a 292 crankshaft offset ground for mock-up purposes to get a 4.000-inch stroke coupled with a 1.889-inch Honda connecting rod journal with 3⁄8-inch rod bolts. He cut a single rod journal down to Honda size and went to work on the mock-up. The main concern was getting 3⁄8-inch rod bolts to clear the camshaft while still getting the lift he needed.
"A smaller base circle cam was not going to help in that I was already planning a camshaft with 0.376-inch lobe lift to get the 0.600-inch-plus valve lift I was looking for. The cam's base circle could be no smaller than 1.150-inch without having the lifters fall out of their bores," Eaton noted. He added that the 1.150-inch base circle camshaft would clear rod bolts only with a 0.337-inch maximum lift lobe.
Once he knew he could get the 4.000-inch stroke inside a 292 block, Eaton could confidently order what he needed to build this engine. He ordered a 4.000-inch stroke Moldex 4340 billet steel crank with 2.4980-2.4988-inch Y-Block main journals and 1.889-inch Honda sized rod journals. Instead of a Y-block crank flange, he opted for an FE/385-series big-block crank flange to make it easier to find an SFI–approved steel PRW flywheel mandated for the Engine Masters Challenge.
 The assembled short-block shows ceramic-coated piston domes and finish work on the block to eliminate stress risers. The ceramic coating protects pistons from extreme temperatures should there be detonation issues.
 Ted ordered a custom cam grind from Isky Racing Cams with 109-degree lobe centers advanced 1½ degrees to 107½ degrees intake lobe centerline, with duration at 0.050-inch at 254/258 intake/exhaust and lobe lift at 0.370/0.376-inch intake/exhaust with 1.6:1 rocker ratio. “If it spins, it probably needs balancing,” which explains why Eaton dynamic balanced this cam and sprocket. This gets rid of any potential vibration issues.
 For those of you unfamiliar with the Y-Block, it takes some getting used to, like these solid tappets that install through the cam tunnel instead of the valley. These guys ride offset on the cam lobes and whirl around for even wear and smooth function. To the best of our knowledge, there isn’t a roller cam available for these engines.
 Eaton has reworked the Mummert plenum as shown, including dimples that help keep fuel droplets in suspension. Much of this is trial and error to see what can be realized in power gains.
 Eaton opted for 1959 vintage 292 iron heads (5752-113), taking valve sizes to 2.02/1.56-inch intake/exhaust, along with some aggressive port work. "There's no flow numbers on these heads because I didn't have a flow bench to work with all the time," Eaton tells us, "This pair of heads has already been milled with chambers at 65 cc's."
Eaton ordered 6.750-inch-long, parabolic-beam Oliver connecting rods with Honda-sized large ends to get a 1.68:1 rod ratio, as well as the dwell time he was seeking at each end of the bore. He added that this made the engine less susceptible to detonation. To achieve 375 ci, Ted went with Diamond ceramic-coated pistons with special low-friction skirt coatings to reduce friction. Compression height was 1.000-inch exactly, which put the wristpin in the ring lands, calling for an oil ring support rail to prevent ring distortion. An 0.866-inch wristpin and 9cc reverse dome cover the remainder of piston dynamics, yielding a 10.1:1 compression ratio.
Working compression ratio (also known as dynamic compression) was 8.0:1 with the cam advanced 1½-degrees and valve lash at 0.025-inch hot. With Ford iron heads, this was how Ted had to do it burning 91-octane fuel. Had there been aluminum heads available at the time of his 2009 Engine Masters experience, he could have pushed compression higher. Aluminum heads conduct heat better than iron, which enables you to run more compression.
Eaton opted for a 3.859-inch bore coupled with a 4.000-inch stroke to achieve 375 ci along with more cylinder wall thickness from a B9AE-F 292 non-steam hole block
|2009 Dyno Testing—Iron 292 Heads|
|Eaton Balancing Dyno|
|Horsepower||460.2 @ 6,100 rpm|
|Torque||448.5 @ 4,800 rpm|
|Engine Masters Challenge Dyno|
|Horsepower||432.7 @ 6,200 rpm (Corrected)|
|Torque||414.0 @ 4,900 rpm (Corrected)|
"When the 375 was assembled, it was placed on the dyno for serious testing," Eaton tells Modified Mustang & Fords, "Seven different intake manifolds were tested, along with a variety of carburetors and spacers. Also tested was a pair of headers—one set from a '23 T-bucket and another being stepped headers provided by Jerry Christenson and Royce Brechler. The final chosen engine combination was the new Mummert intake manifold and a Holley 950hp (834-cfm), and the stepped headers (1.75- and 1.875-inch tubes feeding into modified 3½-inch collectors and mufflers). We got 462-464 horsepower and 446-449 lb-ft of torque through the mufflers, which isn't too shabby for 10.1:1 compression on pump gas." They tried a 1,050-cfm Holley Dominator just to see what happened, and torque increased dramatically.
When Eaton and his crew arrived at the 2009 Engine Masters Challenge in Ohio, they had fuel line troubles and had to go with a spare. "Once the fuel line problem was resolved, the engine fired and ran cleanly at 900 rpm," Eaton tells us, "We had jetted the carb at 77/89, whereas it had been jetted at 75/87 in Texas." A stuck secondary float created its share of problems for Team Eaton, which had to be solved in a short period of time per EMC rules. "A quick look at the data showed our jet change was a good call with the engine peaking at 433 hp and 416 lb-ft of torque," Eaton said confidently, "All of the competitors were getting lower numbers at the competition than seen on their own dynos. Some were down as much as 100 hp. Our Y-Block wound up being just 30 hp down from what we saw in my shop." Eaton chalked up the lower numbers to climate difference and rain during the competition.