Cylinder Block

2 piece rear seal up to 1985

1 piece rear seal 1986 on

This is based on a production 4BM cylinder block with a 1 piece rear seal. It has 4.25” cylinder bores, and the max oversize is +.060”.

Dart

These days it is getting harder to find a decent block to base your performance engine on. The bores can be too thin, with corrosion from behind, there can be hidden cracks, the main tunnels can be out of line, or maybe you just want to build a decent stroker. The little ”M” block is ideal to build your engine from, here are some of its features- uses std small block parts, except for cam bearings which are 2” OD. Extra thick cylinder walls [min .275” with 4.185” bore], priority main oiling system, blind tapped head bolt holes, extra thick decks, centre 3 main caps are ductile with 4 bolts [splayed outer].
Extras required- PP-BYAJG375 rear cam plug, PP-BYGMP-8 2” OD cam bearings, or PP-BYGMP-8T [coated bearings]. On the 400 block, a PP-BY2909 seal will also be required.

Dart

Use this block with a 4” stroke crankshaft, to build a 427cuin Small Block Chevy. Sump rails are spread .400” per side. Sump bolts relocated in line with main caps. Steel 4bm caps, raised cam .391”, Big Block cam brgs.

Dart

Dart have designed a user friendly block, with the features needed for today. The lubrication system is a true- ”priority main” system that feeds all the main bearings before the lifters. A stepped main oil gallery increases the flow of oil to the crank at high rpm. Two extra head stud bosses have been added. Blocks are CNC machined. Siamesed extra thick cyl walls. [.300” thick with 4.625” bore]. 4 bolt ductile main caps.
Crank tunnel has clearance for a 4.5” stroke with steel rods. Dual sump bolt patterns. Bellhousing flange & rear mains are reinforced to resist cracks. 2 piece rear seal. Can be bored to 4.625”. Dart claim this block is good for 2000bhp.

Dart

Use this block with a 4.5” stroke crankshaft, to build a 472cuin Big Block Chevy. Dual sump bolt patterns for both std and notched rails. Steel 4bm caps. Can be bored to 4.625”. Extra head stud positions. With coated cam bearings, core plugs & dowels.