ZR-1 ZR-1 ZR-1 ZR-1 ZR-1 ZR-1 ZR-1
Haibeck Automotive Technology
385 Cubic Inches 565 HP
The stroke is lengthened from 3.66" to 3.82".
The 3.90" cylinder liners are replaced with 4.00" liners from LA Sleeve. Diamond pistons are utilized.
The stock camshafts are utilized. The camshafts are timed to the '93 - '95 specifications, E 110 degrees centerline and I 114 degrees centerline. The engine idles smoothly like a stock engine.
Headers are installed. Click here for more information on headers. A low backpressure exhaust system is required. The Corsa system works best. The B&B Triflow system with an x-pipe also works well.
An aluminum flywheel is installed. Click here for more information on the light weight flywheel and clutch.
The power increase over the 540 HP engine comes from the increased displacement.
The .16" increase in stroke is a reasonable increase over the stock stroke. Stroke lengths beyond 3.82 place a much higher lateral load on the piston skirt in the vicinity of BDC. A longer stroke accelerates long term piston and piston ring wear. 4.125" stroke engines also must use go from a 3/16" (4.75 mm) oil control ring to a 3mm ring in-order to accommodate the higher wrist pin location required for a 4.125" stroke. The smaller oil control ring impacts oil control.
A dyno chart for a 385 with 565 HP. The other run on the chart shows the engine with some previous modifications.