With the power and RPM band of our engines, the number of main bearing cap bolts is of no consequence.

If Timothy has FOUR bolts, then I want four bolts....What size are they anyway?...Maybe I'll just slide two more down the oil tube

Lee:

The notes I found said Z was used for 1973 4 bolt main 454s and S was used from 1974 to I think 1978 or so for the same engine.

Ralph's note suggests that Z and S were used indiscriminately. The web page I visited did not list a 2 bolt 454 in any of our chevy P30s.

Timothy



[This message has been edited by timnlana (edited August 12, 2005).]

Guys my 1974 service man Y= V-8-350-4
Z= V-8-454-4
In my 76 update manual S=V-8 454-4
Y=V-8-454-4
1988 manual W=7.4 V8 4BBL LE8
N=7.4 V8 TBI L-19
THE 4 MUST BE A 4 BOLT MAIN.
RALPH