View Single Post
Old 09-06-2014, 10:13 AM
Fellro's Avatar
Fellro Fellro is offline
Ford Truck Fanatic Administrator

Join Date: Jan 2007
Location: Iowa County, Iowa
Posts: 7,477
Fellro has a reputation beyond reputeFellro has a reputation beyond reputeFellro has a reputation beyond reputeFellro has a reputation beyond reputeFellro has a reputation beyond reputeFellro has a reputation beyond reputeFellro has a reputation beyond reputeFellro has a reputation beyond reputeFellro has a reputation beyond reputeFellro has a reputation beyond reputeFellro has a reputation beyond repute
500 hp 400 on a unique mix of parts...

The Mutt - Over 500hp and 565 lb-ft from Ford's 400m
Starting With An Engine Nobody Wants, The Ford 400M, We Made Over 500 Hp And 565 Lb-Ft With Parts From Ford, Chevy, Mopar, And The Aftermarket

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 Mutt Ford 400M The Ford 400 and 351M engines are based on Cleveland architecture and use small-block bore

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.
The Mutt Piston Comparison Here's a comparison between our new piston/rod setup and the stock parts. The new componen

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.

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 Mutt Cutting Tool The easy answer when it comes to cutting valve pockets for multi-angle valves is this cutt
My trucks:
The workhorse, 86 F250 4x4 6.9 nat aspirated, 3.25 exhaust, custom intake, electric fuel pump, otherwise well used stock... not real pretty but just loves to work!

The other heavy hauler, 92 F350 2wd dually crew cab, flatbed/toolboxes, 92 Cummins VE 12V with intercooler, NV4500 manual

The beater: 88 F250 4x4, 5.8 5 speed
The project ... 1978 F150 4wd shortbed 351 auto

ASE certified parts specialist
I do most all of my own work so I know who to complain to..Roger
Reply With Quote
Sponsored Links