ICON Premium Forged Big Block Chrysler 383 "B" 433ci / 491ci Pistons Flat Top 4.290" Bore

Name: ICON Premium Forged Big Block Chrysler 383 "B" 433ci / 491ci Pistons Flat Top 4.290" Bore
Brand: UNITED ENGINE MACHINE
SKU: 648-IC689.040
Price: 793.48 USD
Availability: InStock

^$793⁴⁸

Ships on 09/15/2026

Lowest Price Guarantee

Chrysler "B" 431ci / 489ci

Flat Top Pistons

431ci Use w/ 6.768" Connecting Rods & 3.750" Crank Stroke

489ci Use w/ 6.535" Connecting Rods & 4.250" Crank Stroke

Big Block Chrysler "B" 433ci / 491ci Forged Pistons

Flat Top

4.290" Bore (+.040'')

433ci - 6.768" Rod & 3.750" Stroke; C/R 10.9/75cc; 10.4/80cc; 9.7/88cc

491ci - 6.535" Rod & 4.250" Stroke; C/R 12.3/75cc; 11.7/80cc; 10.8/88cc

8/pkg.

Technical Notes:

For use with 383 "B" blocks
Stock standard 383 cylinder bore is 4.250" with 3.375" crankshaft stroke
4.290" Bore + 3.750 Stroke = 433ci
4.290" Bore + 4.250" Stroke = 491ci

Technical Specs:

Alloy: Premium High Ductility 2618
Bore: 4.290"
Crankshaft Stroke: 3.750" (433ci); 4.250" (491ci)
Connecting Rod Length: 6.768" (433ci); 6.535" (491ci)
Deck Height: 9.980" (B)
Compression Height: 1.318'
Pin Size: 0.9900' x 3.000"
Pin Location: Centered
Flat Top: 2 Valve Reliefs
Effective Head Volume: 4.5cc
Intake Valve Relief: 0.218' Depth / 2.300' Diameter
Exhaust Valve Relief: 0.199' Depth / 1.880' Diameter
Top Landing Height: N/A
Ring Grooves: 1/16' Top; 1/16' Middle; 3/16' Bottom
Gram Weight: N/A
433ci Compression Ratio: 10.9:1 w/75cc Heads; 10.4:1 w/80cc Heads; 9.7:1 w/88cc
491ci Compression Ratio: 12.3:1 w/75cc Heads; 11.7:1 w/80cc Heads; 10.8:1 w/88cc