TTA PERFORMANCE LLC

Specializing in 1980-1981 Turbocharged 4.9 (301) Pontiac Trans Ams and Firebird Formulas.​

We had the opportunity to rebuild a customers 1981 301 Turbo and have it dyno tested.


The Specs:

Block:

  • 1981 301T Block
  • .030" over bore (making it 306 cu. in.)
  • Forged, Flat Top Pistons
  • Stock Connecting rods, shot peened and fitted with ARP Rod Bolts
  • Stock 301T Crankshaft
  • Moly piston rings
  • TTA Performance 252H Comp Cam and 301 Lifters
  • Comp Cam true roller timing chain
  • Luhn Performance grooved cam bearings
  • One Piece Viton Rear Main Seal

Heads:

  • 1981 301T cylinder heads
  • Ported behind the valve seats on intake and exhaust (ports are still stock size)
  • Removal of AIR pump "bump" in exhaust port
  • Narrowed valve stem casting boss
  • Stock size valves with performance valve job and back cutting
  • Stock intake ports and intake manifold ports (no porting)
  • TTA Performance head gaskets
  • Stock 1.5 ratio rocker arms

Turbo and misc.

  • TTA Performance upgraded turbo
  • Ported carb plenum to match turbo
  • 1980 301T carb with upgraded jets and metering rods (for dyno)
  • 1980 301T distributor ESC by passed (for dyno)
  • TTA Performance 2.5" down pipe
  • TTA Performance prototype shorty header system
  • TTA Performance water/alcohol injection
  • TTA Performance manual boost controller (set to 14 psi)
  • Stock 1980 air cleaner and paper air filter
  • TTA Performance plenum coolant hose (engine tested at 140° water temp)
  • 93 octane pump gas
  • Timing set to 30° total timing


Power out put was 354hp @ 4500 RPM  511 lb/ft torque @ 3000 RPM!



Turbo 4.9 on the dyno