Mercruiser 165hp GM 250ci Engine Bored .030 Oversize with New in the box Silv-o-lite TRW-3302LF Pistons, Stock Valves and Springs 3837760 Head(hardened seats) with a Quicksilver Marine Camshaft, 2008 Sierra Marine Carb, Aqua Power Riser, New Drain Petcocks, Rebuilt 65 amp Altenator, Stripped and Satin Polished Rocker and Lifter Covers. When I got the boat I found that the rockers were not completely adjusted as most were clacking. I took care of that and found the engine ran great. >> When I went to rebuild then enigne Ted Wingate found that the #6 rod was bent I got him an exact match be he did a partial blueprint of the engine (pistons, rings, rods, crank etc.. ) but he still did a full balance of the rotating assembly within a “couple tenths” of a gram!!!

Listed below are 2 types of dished pistons available.

L6 250	1966-84	3" dia. "D" head recess .060" deep.	1446	2/5/1964	3886040	3874468
4.1 L			Std.	1/3/2016	3886048	3877604
3.875(IN)	8.4	APPROXIMATE HEAD VOLUME=7cc	0.02		6270033	6262805
98.4(MM)			0.03
		Comp. Ht. 1.640	0.04
CHEVY		Pin Dia..9273 Offset	0.06
ENGINE
L6 250	1966-90	3.080" dia. head recess.270" deep. Low compression engine.	3454	2/5/1964	3877610	.
4.1 L			Std.	1/3/2016
3.875(IN)			0.02
98.4(MM)		Comp. Ht. 1.660	0.03
		Pin Dia..9273 Offset	0.04
CHEVY			0.06

STD. BORE SIZE
3.875 / 98.4mm


COMP. HEIGHT
1.64


PIN DIAMETER
0.9273
offset


COMPRESSION RATIO(s)
8.4

VIN CODE



RING PACK
2-5/64
1-3/16

O.E. ASSY. NO.
3886040
3886048
6270033