Major Engine Power Upgrades
Component Packages for a 350 Cubic Inch Engine
Upgrade: '90-'92 HP '93-'95 HP
Original equipment engine power 375 405
Low back pressure exhaust system +10 +5
Performance engine calibration (chip) +10 +10
Subtotal 395 420
Headers +25 +25
Subtotal 420 445
Top End Porting +30 +20
Subtotal 450 465
Cylinder Head Porting +45 +30
Subtotal 495 495
Aluminum Flywheel +15 +15
Total HP 510 510
Click on a link below for additional details about the upgrade component.
Headers Top End Porting Cylinder Head Porting Aluminum Flywheel
Complete Engine Packages
The 510 HP 350
- Full porting, sized for a 350 cubic inch engine.
- Headers
- Fidanza aluminum flywheel
- Stock camshafts, smooth idle.
- If driven well, this engine will run 12.1@120 mph in the quarter mile.
- The most performance for your LT5 upgrade dollar $14,940.
368 Cubic Inches, 540 HP
- Four inch liners with Diamond pistons
- Full porting, sized for a 368 cubic inch engine.
- Headers
- Fidanza aluminum flywheel
- Stock camshafts, smooth idle. $23,900.
385 Cubic Inches, 565 HP
The 385's place in LT5 history.
One of my favorite engines, the original 385's were built by John Lingenfelter and Doug Rippie. They used a long stroke version of the crankshaft made by the OE LT5 crankshaft supplier Shardlow in England. Shardlow ceased to exist after a reorganization in about 1997. After that, crankshafts were acquired from US suppliers. The LT5 crankshaft is complicated to build and thus is very expensive. This accounts for the large price difference going from a 368 to 385 ci. Since a 415 crankshaft costs the same as a 385 crankshaft, it makes sense to build a 415 if incurring the expense of a custom crankshaft. We can build a 385 today. However, as a practical matter I recommend a 378 ci engine if an LT5 with a conservative stroke is desired. See the description of the 378 below.
- Four inch liners with Diamond pistons and Molnar rods
- Full porting, sized for a 385 cubic inch engine.
- Conservative 3.820” stroke crankshaft maximizes durability
- Headers
- Fidanza aluminum flywheel
- Stock camshafts, smooth idle. $30,120.
378 Cubic Inches, 555 HP
- Four inch liners with Diamond pistons and Molnar rods
- Full porting, sized for a 378 cubic inch engine.
- Conservative 3.760” stroke crankshaft maximizes durability
- Headers
- Fidanza aluminum flywheel
- Stock camshafts, smooth idle. $25,670.
415 Cubic Inches, 590 HP
- Four inch liners with Diamond pistons and Molnar rods
- Forged 4.125” stroke Moldex crankshaft. 4340 steel material.
- Maximum porting
- Large intake and exhaust valves
- Headers
- Fidanza aluminum flywheel
- Stock camshafts, smooth idle. $32,360.
415 Cubic Inches, 650 HP
- Four inch liners with Diamond pistons and Molnar rods
- 4.125” stroke Moldex crankshaft. 4340 steel material.
- Maximum porting. The plenum port septum is removed.
- Large intake valves
- Headers
- Fidanza aluminum flywheel
- Extended duration camshafts, choppy idle.
- If driven well, this engine will run 10.9@130 mph in the quarter mile. For use at the drag strip a high torque capacity clutch is required. It is not included in the engine package.
$37,910.
730 HP LS9
- 19% supercharger overdrive
- Porting for the supercharger inlet and the throttle body
- Installation of protective air flow shields on the intercooler bricks
- Haibeck Automotive Technology tuning
$5,450.
The chart shows 743 crankshaft HP because the car ran with light weight CCW 18 inch wheels and ET Street tires. They are nine pounds lighter than the OE wheels and tires. Expect 621 wheel HP/730 crankshaft HP with the OE wheels and tires.
All Crankshaft HP Specifications Are Calculated From Measured Dynojet Rear Wheel Power.
The calculation assumes a 15% power loss through the drive line.
WHP/.85 = CHP
For example: 550 WHP/.85 = 647 CHP