HOW TO BUILD A 425-450HP 460ci
The request for information for a mild 425-450hp street motor comes up weekly, so I thought we'd compile a list of parts that will accomplish this goal. Obviously, there is quite a bit of room for interpretation and variance on parts, but a good SEARCH will help sure up any remaining questions.
Edelbrock Performer, Performer RPM, or Weiand Stealth
Hydraulic flat tappet cam with approx 215-220* intake/225-230* exhaust duration. Lift should be in the .525"+ area to take advantage of the quicker lobes allowed by larger diameter lifters in Fords.
Examples would be the Comp XE262H or Lunati 61602
Compression should be around 9:0-9.5:1
Stock rods and crank can be used with good resizing and good bolts used
Heads can be DOVE or D3VE
Exhaust valves should be increased to 1.75" size
Intake valve size does not need to be increased at this level, stainless valves are suggested over heavily used stockers
Port work on the exhaust side should be considered MANDATORY at this level. Thermactor removed, bowl blended to the larger seat, casting flash removed, exhaust bolt boss flattened. The better the work, the better it will run. To get to a real 450hp level, it would be very beneficial to at least clean up the intake side, the seat to bowl blend at minimum. A good 3 angle valve job is mandatory. A D3VE head does have enough potential for this build but may require more short turn work on the exhaust side to match the DOVE. An aggressive cam like the Lunati probably requires the screw in stud conversion on the D3VE as well.
Exhaust should be minimum 1 3/4" headers to dual 2.5" pipes with good flowing mufflers. Manifolds will absolutely not allow the engine to perform as expected.
Roller rockers are not mandatory, but suggested. A HV oil pump is not required at this level, as the RPM level doesn't dictate loose tolerances. Standard .0025 and .0030 on rods and main should work fine, a bit tighter would probably be fine as well since the motor shouldn't see anything over 5500rpm.
Good machining and port work should allow a motor like this to last forever, creating a solid 425-450hp at around 4500rpm and 520-530ft lbs near 3500rpm.