GPI products are usually in stock and ship fast.  If you want to double check please feel free to email

LT1 CNC PORTED HEADS - pair - (no core required)

Our LT cylinder heads were developed specifically for the stock displacement LT engines to deliver improved cylinder fill in the lower RPM ranges while adding substantial airflow increase in the upper ranges as well. Our testing has shown over 30 hp increase while improving torque below the curve.

GPI makes the best performing Cylinder Heads you can buy!

OEM Casting ported and chambered – with valves less springs.

Intake Port Volume:  320cc

Exhaust Port Volume:  116cc

Lift  Intake Flow @ 28″  Exhaust Flow @ 28″ w/ No Pipe
.300 232 158
.400 293 204
.500 340 237
.600 354 252
.700 368 259
.800 383 262
.900 391 264


Price is includes core charge.   If you would like to return your stock heads you will get a $1000 refund