Turbo Pontiac 400 Build - Cam Specs and Turbocharger

Tale Of The Tape
Cubic Inches	Bore	Stroke
400	4.12	3.75
489	4.16	4.50

Cam Specs
Comp Cams	Advertised	Duration	Lift
XFI Custom	Duration	At 0.050	At 1.5:1 Rocker
Hydraulic Roller	(Degrees)	(Degrees)	(Inches)
Intake 3015B lobe	274	224	0.537
Exhaust 3036B lobe	282	230	0.533
Lobe-separation angle	114

The Turbo
While many of the described parts may seem overly restrictive given the search for power, the one overriding factor that makes up for much of this is the turbocharger. Back in the day, Crocie used a rather small Rajay turbo. Now that hair dryers have had almost 30 years to improve, he sought help from PT Turbochargers to give this original spinner a much-needed boost. He gave the original turbo back to the customer and started from scratch. The entire compressor housing side was exchanged for a much more modern 60mm Rotomaster. Mounting the turbo in the original location with the same bracket demanded an original Rajay exhaust housing, but it was too small at 1.0 A/R, so Performance Turbos dug up a sole-surviving 1.3 A/R Rajay housing. Along with an equally rare Rajay centersection using newer compressor and exhaust turbine wheels, this turbo is definitely a one-off piece.

Notice how much more open and free flowing the new compressor side (right) appears compared with the original Rajay turbo (left). The exhaust housing was also increased to help the larger engine breathe.
Notice how much more open and free flowing the new compressor side (right) appears compare
This photo shows the final installation and the turbo's mounting plate.