Guys

To upgrade a 94 non vented opti to a 95 vented opti, do you have to change cams? I was reading a site, probably shoebox's, and it gave all the parts. But then it said that due to how the opti fits into the cam, the 95 up cam is machined differently from the 94. I have a 95 vented opti and all associated parts, so other than gaskets I would like to put the vented opti in once my 94 dies. But after reading this I am not so sure. Let me know what I can or cannot do as far as upgrading my 94 T/A to a 95 vented opti.

tia

Andy Schuck
94 T/A k&n cai, hooker catback, taylor wires, descreened maf, slp y pipe, more to come!!!

 

When I installed my new cam, there is a pin on the cam that drive the chain I think...but I dont think the cam face needs to be any different that what you have.

 

On my Y-body '92 LT1, I definitely had to change the cam to upgrade to the '95 Opti-Spark.
The hole in the center of the '92 cam was too small for the '95 Opti-Spark to fit into.

Tom Piper

 

Oh yeah, that's what I was trying to say

 

The hole in the cam? I know the dowl pins are diferent but you can change that w/o having to swap the cam and the the timing covers have diferent size holes but am not shure what you mean by the hole in the cam.

 

This has nothing to do with dowel pins, but the dowel pin length did change.

The later vented Opti-Spark has to fit into (that's right, go inside) the front of the camshaft. The later Opti-Spark has a shaft, with two "O" rings on it, that fits into the camshaft. And, the camshaft has to have a center hole in the front that is big enough for the Opti-Spark shaft.
The early Opti-Spark did not have this shaft and my '92 camshaft did not have a hole big enough for the later Opti-Spark to fit into it.
I did read somewere that GM changed this in later engines, so a '94 camshaft my not need to be changed to accept a '95 up Opti-Spark.

Tom Piper

 

http://para.noid.org/~muttvette/opti.html

 

This often linked site has pictures of the front profiles of the cam and how they are different.

The hole in the nose of the cam for the vented opti is .500" in diameter and 1.0625" deep.