Ford's 400 engine isn't the usual candidate for a horsepower buildup, and it fought us at many steps along the way, but the results are worth it. Consider it a Dare To Be Different engine.
Engine designs can be a lot like politics: Sometimes the results are inspired-like Chevy's small-block or the classic Chrysler Hemi-but quite often the finished product is a big, fat compromise that nobody particularly loves. That second scenario was the case when Ford debuted the 400 in 1971.
The 400 was intended as a replacement for Ford's aging big-block designs. The block's architecture borrowed heavily from the Cleveland, including the bore spacing, but 1.09 inches of additional deck height were added to allow a 4.00-inch stroke and the potential for plenty of torque. Unfortunately, this engine's debut was also horrifically timed. The confluence of increasingly harsh government pollution standards and the disappearance of high-octane leaded fuels left the 400 castrated in terms of its performance potential. A retarded camshaft, low compression, open combustion chambers, and other smog-control measures conspired to drop the rated output for this 400ci engine to a pathetic 158 hp between 1975 and 1978.
The Ford 400 and 351M engines are based on Cleveland architecture and use small-block bore centers. The extra-tall 10.297-inch deck height means a 4.200-inch stroke is easily attained.
So you can see why the 400 (and Ford's 351M, which has a 3.50-inch stroke rather than the 400's 4.00-inch) has been written off by hot rodders as a pig. Of course, that only adds to the fun of finding out exactly what this engine is capable of, so we decided to see how much power we could make out of one without totally breaking the bank. We wanted to use readily available components, meaning no Australian heads or anything else that depends on a lucky find or endless hours trolling the Internet. The lack of much aftermarket support for this engine may limit it a little more than a conventional Windsor, but that's OK. When we get done, there won't be anything else like it out there. Performance engine builder KT Engine Development in Concord, North Carolina, assisted with planning the parts package and handled almost all the engine machine work; it's that company's prices we are quoting in the recipe list, but we are assuming you'll handle all the assembly work.
While Ford Windsors, 429s, and 460s are getting more expensive, 400s and 351M blocks still populate junkyards like rusty hubcaps. After calling around to a few junkyards, we found that you can get a complete 400 short-block for around $125. A full donor engine should be in the $200 range. However, if you can get all the pulleys, brackets, and other little stuff off the engine (dipstick tube, oil pan, valve covers, and so on), a short-block is all you need. If you are junkyard hopping, 400s can be found in '71 through '82 Ford pickups, vans, LTDs, and some other larger cars. If you find a good 351M, that can work, too. You will just need to find a 400 crank.
The biggest challenge throughout the build is that, with one big exception, there are really no aftermarket performance parts for this engine. The one bright spot is the new Edelbrock aluminum Cleveland-style cylinder heads that will fit this block. These heads utilize the Cleveland's canted valve angles for minimal valve shrouding, Yates-style 60cc (although our measurements were closer to 62) combustion chambers, and modern port designs that are a considerable improvement over the stock, open-chamber heads. The Edelbrocks are a bit pricey at $909 each, but they come complete and are a huge improvement over the stock units.
Edelbrock also produces one of the few intake manifolds designed to work with this engine. It is a low-rise dual-plane intended more for low-rpm use than a big-horsepower unit like we are building, but it is also a big improvement over the stock piece. And at $194.88 from Summit Racing, the cost-to-value ratio is pretty high. Although it won't show up on the dyno, a secondary but very real benefit of these aluminum pieces is weight savings off the top of a moderately heavy engine package-the aluminum heads and intake chisel 83.5 pounds off of the top half of the engine.
The bottom half of the engine throws up a few more obstacles. The stock 400 uses a 10.297 deck height, 3.00-inch main journals, and 2.311-inch rod journals. That wouldn't be a problem except there is no such thing as a set of forged pistons or rods for this engine. Direct-replacement piston choices are limited to stock cast pistons, which will never survive with the power levels we intend, or a way-too-expensive set of custom forgings. So, we had to think outside the box. We took our crank to Kannapolis Engine Machine and had the company offset-grind the rod journals down to 2.100 inches and bring the stroke up to 4.200 inches. That allowed us to run slightly modified rods for a Chevy small-block (which had to be narrowed to fit the Ford's crank journals). The longest Chevy rods we could find that were reasonably priced were 6.300-inch H-beams from a relatively new company called K1 Technologies. Central High Performance will sell you a set for $399.46. That still left us 1.897 inches short of filling the cylinder bore, and the answer there turned out to be pistons for a Dodge 340 V-8 with 1.840-inch compression heights.
Here's a comparison between our new piston/rod setup and the stock parts. The new components cut the bob weight by 452 grams.
With this combination, we were able to deck the block 0.027 to get a piston deck clearance of 0.030 inch. The intake manifold still fit without milling. The standard bore for the Mopar-340 pistons is 4.040 inches, so that dictated a 0.040 overbore for the forged block, which is well within the safe range. KB Performance Pistons hypereutectic units are stronger than the cast slugs that originally came in the engine and sell for just $27-and-change each including the wristpin. The pin on these pistons is a hefty 0.9842 in diameter, which meant the rods had to be reamed out from their bushed diameter of 0.924 inches. This also eliminated the bronze bushing, but the rods have two oiling holes, and if they are properly clearanced, running steel on steel shouldn't be a problem.
The 4.200 stroke combined with the 4.040 bore brings the cubic inches up to 431. The extra inches were welcome, but in the process, we also created our next fitment issue. The stock crank is designed to work with the original 6.5815-inch connecting rod and heavy piston. To make the shorter rod/piston combo fit required cutting off 0.495 inch from the highest point of the counterweights, which left us with too little weight to counteract the rotating/reciprocating assembly. The lighter rod/piston assembly lightened the bob weight from 2,396 grams to 1,944 grams, but with the lathe work, the counterweights were way too light.
This engine is externally balanced, so the easiest way to bring everything a little closer to the correct balance is to use a 164-tooth flexplate and balancer for a late-model 5.0/302 Ford instead of the stock 400 damper and flywheel. The Ford stuff uses a heavier balance weight for the 50 oz-in factory balance setup, which reduced the amount of Mallory metal used in the crank. A 302 balancer is also about $50 less than a stock replacement balancer for the 400. The only problem is that the 302 balancer forces the crank pulley farther out from the crank. To even things up, we used a generic fan spacer purchased from Advance Auto and cut it to size to move the water-pump pulley out the correct distance. That, in turn, will force cutting spacers to get the alternator and power steering belts lined up when the engine actually goes into a car. The other option is to cut down the front of the damper on a lathe.
The 0.598-lift valvetrain necessitated a spring upgrade. The answer was a set of Comp Cams 929-16s, which upped the rates to 150 pounds on the seat and 420 open and fit right without changing spring seats or retainers.
For the valvetrain, we debated using a budget solid flat-tappet cam and lifters but decided to go with a lower maintenance hydraulic roller system. Yes, a flat-tappet camshaft is cheaper, but for the performance levels we are looking for, a flat-tappet cam should be nitrided, which usually adds an additional $125 or so to the cost. The cam is a custom grind from Crane Cams with 234 degrees of duration at 0.050 lift for both valves and a lobe lift of 0.352 inch. With the Chevy-style 1.7:1 Crane Energizer roller rockers, the total valve lift is 0.598 inch. Although the stated maximum lift from Edelbrock for the heads is 0.600, we found they can actually stand a little bit more, thanks to the 1.900 spring height, if you change the springs. The springs supplied with the heads (130 pounds on the seat and 340 open) weren't quite strong enough for the fairly radical cam profile, so they were replaced with a set of PN 929-16 springs from Comp Cams that upped the rate to 150 and 420, respectively. These heads also use pushrod guideplates, so we had to shell out $123 for high-end chromoly 51/416 pushrods from CV Products.
The easy answer when it comes to cutting valve pockets for multi-angle valves is this cutting tool from Isky. It is essentially a valve with a cutting face on the end. Slide it into the valveguide of the cylinder head, bolt the head down to the block with the piston to be cut at TDC, and spin the cutting tool to cut your valve pocket exactly where it needs to be. It isn't suitable for cutting large pockets, but we only needed an additional 0.060 clearance, and for that it worked fine.
The last step before final assembly was getting the valves, complete with their Cleveland angles, to fit with the flat-top Dodge pistons. We clearanced the pistons' valve pockets with Isky's new valve-pocket cutting tool. The cutter should only be used to cut smaller-sized valve pockets, but it was perfect for this project. Best of all, Isky will rent it to you for $40. Only the intake valve needed clearance, and we cut the pocket about 0.060 deep to create 0.095-inch valve-to-piston clearance.
We had initially picked up a remanufactured points distributor for approximately 40 bucks, but the 10.6:1 final compression ratio made us think twice about using it. With aluminum heads and a reasonable timing setting, that's doable in a lightweight car with a good radiator, but a 6,000-rpm redline is probably too much for an old points distributor. So just before bolting the engine to the dyno, we dumped the stock ignition for a Pro Billet distributor and coil from MSD that we stole off another engine. It isn't the best way to go if you are counting every penny, but the MSD system performed flawlessly on the dyno.
Our stated goals at the beginning of the project were to produce 500 lb-ft of torque and 500 hp. On the dyno, it became apparent that the intake manifold limits this engine's ability to breathe at the upper-rpm levels. The long stroke makes for excellent torque production with a nice, flat curve, but our first runs fell just short of the 500hp goal. We had already anticipated the limitations of the dual-plane intake and fitted a 1-inch open spacer under the Holley 870 carb. The results were 556 lb-ft of torque and 496.7 hp. Close, but not quite there. A second 1-inch spacer got us there. This time around, the torque peaked at 565 at 4,300 rpm and the horsepower was 505 at 5,300. It certainly would be interesting to see how much a single-plane intake could help this combination. Thanks to the efficient combustion-chamber design of the Edelbrock heads, the best timing was at 30 degrees BTDC. The power curve is also pretty flat-at 5,900 rpm, the horsepower had only dropped 15.2 from peak.
The toughest part of this engine build obviously comes from the fact that it isn't supported by the performance aftermarket. The fact that it uses Dodge pistons, Chevy rods, and a Ford 302 balancer is pretty cool, but it does also require a little extra attention to get everything to fit together properly. The total cost also turned out a bit higher than we originally calculated, but comparing it with the cost of building a standard Ford or Chevy small-block just isn't fair, either. Still, rocking a 500hp Ford that most people have written off as a low-power pig is pretty cool any way you look at it.
Dyno Results RPM Torque HP 3,800 559.2 404.6 3,{{{900}}} 560.8 416.5 4,000 562.5 428.4 4,{{{100}}} 564.1 440.4 4,{{{200}}} 564.4 451.4 4,{{{300}}} 565.0 462.6 4,400 560.6 469.7 4,500 554.2 474.9 4,{{{600}}} 550.0 481.7 4,700 545.6 488.2 4,800 539.7 493.2 4,900 532.5 496.8 5,000 525.2 500.0 5,100 518.7 503.7 5,200 507.2 502.2 5,300 500.4 {{{505}}}.0 5,400 489.9 503.6 5,500 482.0 504.8 5,600 470.4 501.6 5,700 456.4 495.4 5,800 445.6 492.1 5,900 436.0 489.8 Average 522.3 477.7Will It Fit?
One oddity of the 400 is that, although it is technically a small-block, the transmission side of its bellhousing mimics the 429 and 460 big-blocks. It also uses the same motor mounts as a 429 and 460. If you already have one of these in your car, you will be set, but if not, you will need to locate a tranny that was originally mated with either a 400, 351M, 429, or 460 to get the power to the back tires. If you are using a car that was originally equipped with a Windsor, all you need to do is replace the Windsor motor mounts on the frame with 400 mounts. There may, however, be hood- and fender-clearance issues. While the 400 has the same bore centers as the Windsor and Cleveland engines, the tall deck height makes the engine taller and wider. Cleveland headers will bolt to the engine, but they will be moved closer to the fenders, and the headers may not clear suspension components. In many applications, a 400 will fit, but be prepared to do a little sheetmetal work.
Cylinder Heads
Edelbrock No. 61629
Combustion chambers:60 cc (62 cc observed) Deck thickness: 51/48 inch Intake runners: 190 cc Exhaust runners: 75 cc Valves: 2.05 intake/1.60 exhaust Valvesprings: 1.540-inch od 1.900 installed height 0.600 max lift Rocker studs: 71/416 hardened steel
Critical Data Bore 4.040 Stroke 4.{{{200}}} Piston height 0.030 below deck Piston volume Approximately 15 cc Compressed gasket thickness 0.040 Compression ratio 10.6:1 Camshaft Hydraulic roller Duration (at 0.050 lift) 234 intake and exhaust Lobe lift 0.352 Valve lift (with 1.7 rocker) 0.609 Spring pressures 150/420 DESCRIPTION Manufacturer PN source Amount Price Donor engine {{{Ford}}} Junkyard 1 $150.00 Valve covers Ford Junkyard 1 15.00 Stroke crank KES 150.00 Machine work KT Engines 1,000.00 {{{Dodge}}} 340 pistons KB KB243 {{{Summit}}} Racing 8 220.69 Rings Sealed Power E251K40 Summit racing 8 35.95 Water pump WP399 Advance Auto Parts 1 29.88 Gasket kit Fel-Pro FEL-KS2308 Advance Auto Parts 1 52.95 Intake gaskets Fel-Pro FEL-1240 Summit Racing 1 16.95 Heads Edelbrock 61629 Summit Racing 2 1,818.78 Valvesprings Comp Cams {{{929}}}-16 Summit Racing 1 136.95 Intake manifold Edelbrock 2171 Summit Racing 1 194.88 Holley 870 Holley Street {{{Avenger}}} 80870 Summit Racing 1 435.95 Carb spacer (2-inch) Mr. Gasket 6007 Advance Auto Parts 1 35.88 Oil pan Milodon 30927 Summit Racing 1 232.95 Oil pump Melling M84A Advance Auto Parts 1 28.88 Oil-pump shaft Clevite 6011431 Advance Auto Parts 1 4.49 Oil-pump pickup Milodon 18355 Summit Racing 1 37.95 Fuel pump Carter M6978 Advance Auto Parts 1 22.44 ARP head bolts ARP 154-3604 Summit Racing 1 {{{57}}}.95 Timing chain Sealed Power KT3-498SA2 Summit Racing 1 23.99 Forged con rods K1 Technologies CH6300ALLBS Central High 8 399.46 Crane roller cam 52HR00032 Crane Cams 1 360.00 Roller lifters Ford {{{M}}}-6500-R302 Summit Racing 16 119.95 Lifter adapter plate Comp 31-1000 Summit Racing 1 49.39 Pushrods CV Products 8.750 x 5/16 CV Products 16 123.04 Rocker arms Crane Energizer 13744-16 Summit Racing 16 195.95 Main bearings Sealed Power 5078M1 Advance Auto Parts 1 23.48 Cam bearings Sealed Power 1403M Advance Auto Parts 1 17.77 Rod bearings Clevite CB-1227 P Summit Racing 8 83.12 Distributor MSD 8580 Summit Racing 1 225.95 Wires MSD 31339 Summit Racing 1 78.88 Coil MSD 8202 Summit Racing 1 34.88 Plugs Autolight 3924 Advance Auto Parts 8 21.44 Header Dynomax WLK-85064 Summit Racing 1 135.95 Damper 15950147 Advance Auto Parts 1 59.88 Flexplate 2922510 Advance Auto Parts 1 47.97 Paint Dupli-color Ford Blue & Silver Advance Auto Parts 2 8.{{{80}}} Fan spacer 252012 Advance Auto Parts 1 8.88 Oil Valvoline 5W30 (4 qt bottle) Advance Auto Parts 2 21.56 Misc. bolts KT Engines 50.00 Oil filter Fram PH8A Advance Auto Parts 1 3.88 Total $6,772.74 Extras Piston-notching tool Isky PNT-216 Isky 1 40.00 Valve covers Edelbrock 4461 Summit Racing 1 39.88 Total $6,837.{{{62}}}