Small-Block Ford 408ci
We've seen naturally aspirated 500hp 302s, and they're rowdy and right on the verge of disaster. On the other hand, the 351 Windsor-based engine that came in fullsize cars and trucks from 1969 all the way to about 2003 has the displacement for good torque and with the right combination of parts can make an easy streetable 520 hp.
The guys at Coast High Performance build Windsor-based 408s with 4.00-inch strokes and 4.030 bores using tall-deck 351s and 6.2-inch rods. The preferred block is from the Ford Lightning truck that has a factory roller cam already installed, but short of that, the '82-and-later block has the one-piece rear main seal, and you can buy a roller-cam retrofit kit with a small base circle so the lifters will clear the dog bones. Then you just drill and tap for the lifter galley spider. All the blocks require clearancing for the rod bolts when using the stroker crank, and Coast suggests using a main girdle for combinations approaching 500 hp and engine speeds nearing 7,000 rpm. For only $169, the girdle is cheap insurance. Another trick is finding a '69-'70 block that has thicker cylinder walls and will take a 0.060 bore for a rebuild later. You can also step up to a Ford Motorsports block for another $1,000 to get the thick walls, one-piece rear main seal, and roller cam in one package.
The cam choice is the Crane 248/256 at 0.050 duration hydraulic roller with 0.595/0.605 lift ground on a 110 lobe center. It may sound a little radical, but at 408 inches, Coast reports it is actually very docile and driveable. Coast uses the AFR 205 street/strip heads that flow 306 cfm right around 0.600 lift. It can be used out of the box after you set the seat pressure to match the cam. For carbureted applications, Coast uses the Edelbrock Victor Jr. single-plane intake, Holley HP 750, and an engine compression ratio of 9.5:1. The fuel-injected applications get 10.0:1-10.5:1 because they usually have better fuel and timing control.
The 408 will fit in your Fox-body or Cobra kit car with a cowl hood, and there are off-the-shelf headers for '64-'66 Mustangs. The Fox engine mounts are the same for the 351 and the 302, you'll just have to use a Fox oil pan.
Using 1 3/4 long-tube headers, this combination should make 520 at 6,300 rpm, which is the limit of the lifters, and 490 lb-ft at 4,200 rpm. The typical Fox-body will be around 3,200 pounds with a five-speed, and a 3.73 gear will give you mid-11s at 120 mph.
Coast High Performance
Description PN Source Price
AFR 205 cylinder heads 1450 Coast High Performance $1,699.00
Crane hydraulic roller cam 13892 Coast High Performance 299.00
Roller retrofit kit 11956 Coast High Performance 69.00
4340 4.00-inch forged crank 10009 Coast High Performance 599.00
Edelbrock Victor Jr. intake 2981 Summit Racing 257.95
Probe 1.6 rocker arms 11273 Coast High Performance 269.00 set
Reverse-dome pistons (9.5:1) 12360-30 Coast High Performance 535.00 set
Holley HP 750 carb 0-80528-1 Summit Racing 438.00
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