where is the vacuum line.
Opti Spark Question
Thread Starter
Melting Slicks
Joined: Apr 2000
Posts: 2,408
Likes: 3
From: Bel Air Md
Opti Spark Question
Before I bought this 93, the prior owner had a GM dealer replaced the opti spark distributor on 2-16-05 which failed due to a water leak on the pump. Hard to believe, I know 
Question, the dealer installed a part # 10457702 distributor. How could I tell if this was the upgraded or vented one, or just an exact replacement for the original non vented one. 
Question, the dealer installed a part # 10457702 distributor. How could I tell if this was the upgraded or vented one, or just an exact replacement for the original non vented one.
Race Director
Joined: Jan 2002
Posts: 12,261
Likes: 85
From: O'Fallon Missouri
To upgrade the opti to the 95/96 version. The dealer would have to change the timing cover, opti, opti wire harness, opti vacuum harness, and the camshaft's dowel pin. It would be a vey expensive upgrade to be done at a dealership.
Check your intake bellows for a vacuum line.
Check your intake bellows for a vacuum line.
Racer
Joined: Jun 2006
Posts: 408
Likes: 0
From: Elkton MD
Optispark vent line
Tried to post a pic but the 'system' won't allow it (must be a neophite).
The vent line is a small black hose with a gray elbow attaching it to the top of the 'bellows' air inlet hose, just about even with the alternator pulley.
The vent line is a small black hose with a gray elbow attaching it to the top of the 'bellows' air inlet hose, just about even with the alternator pulley.
Melting Slicks
Joined: Mar 1999
Posts: 2,535
Likes: 2
From: Rochester NY
I run Delteq on my 93. Glad I did. i like it. The 92/93 opti is way to expensive. The 94-96 are much cheaper but required to change timing cover and cam shaft dowel pin. The delteq is far better than any GM and aftermarket opti. The delteq don't need to MSD box to add extra energy to the spark plugs. As obvious its multi coils pack.
Safety Car
Joined: Feb 1999
Posts: 3,504
Likes: 4
From: Mexico Beach FL
In order to put the later vacuum vented Opti-Spark on my '92, along with the other parts mentioned above, I had to change the camshaft.
The early LT1 camshaft does not have a center-hole in the front that is big enough for the later Opti-Spark to fit into.
Tom Piper
The early LT1 camshaft does not have a center-hole in the front that is big enough for the later Opti-Spark to fit into.
Tom Piper
Team Owner
Joined: Mar 2001
Posts: 30,847
Likes: 293
From: Boston, Dallas, Detroit, SoCal, back to Boston MA
Le Mans Master
Joined: Jan 2003
Posts: 8,596
Likes: 19
From: Portland Oregon
Originally Posted by HG
Before I bought this 93, the prior owner had a GM dealer replaced the opti spark distributor on 2-16-05 which failed due to a water leak on the pump. Hard to believe, I know Question, the dealer installed a part # 10457702 distributor. How could I tell if this was the upgraded or vented one, or just an exact replacement for the original non vented one.
Question, the dealer installed a part # 10457702 distributor. How could I tell if this was the upgraded or vented one, or just an exact replacement for the original non vented one. That part number is the early version.
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