necking down after collecter?

It is a BPE 408 with the following specs:

· HP & Torque: 445 HP / 500 FT LBS
Compression Ratio: 10.1:1
Aluminum Heads
Flat Tappet Cam
Cast Steel Crank
Forged Pistons

Block:

· Hand picked seasoned block
Square and parallel decked
Align honed main bearing bore
Cylinders honed on computer controlled machine to within .0002 straightness and roundness
Cylinders are sonic tested for thickness
2-Bolt Main
4.000" Bored .040" over
2-Piece Rear Main Seal
Mech fuel pump provision: Yes

Rotating Assembly:

· New Cast steel crankshaft
4.000" Stroke
OEM type 6.123" connecting rods w/ 150,000 psi bolts
Forged pistons
External

Cylinder Heads:

· Aluminum Cylinder Heads - 63cc chamber
2.02" intake/1.60" exhaust valves
171cc intake/77cc exhaust runners

Cam Specs:

· Cam Type: Flat Tappet
.545 Intake .545 Exhaust
241 Intake / 247 Exhaust duration
@ .050 - 110 degree lobe separation

Ignition Timing:

· 34 degrees total at 2500-3000 RPM