I see tons of posts that you must change the opti and timing chain when putting a cam in older LT1's. Why? What is the diffrence with the cam exactly? Does it have something to do with the dowel in the cam or am I missing something? Just seems that you should be able to make it work.

 

I'm assuming it just depends on whether the cam is made for a '93 or not.... I think the main difference is the dowel length?

-Michael

 

You don't have to change everything when doing a cam in a 93. The dowel pin on the 93 I believe is shorter than later years, so it must be pushed in/ground down/swapped with your old one, whatever you have to do.

The reason most choose to do the opti and timing is because everythings already out, and it's preventitive maintenance, what with the newfound power coming out. A lot of guys choose to upgrade the opti to the 95+ vented system that helps it dispel liquid if it gets wet, increasing the life of the opti. This way, you can also install an aftermarket timing chain, like a Cloyes True/Double roller or the LT4 HD one.

 

The cam dowel needs to be shortened to use it in a '93-'94. It's no biggy, though. I used a bench grinder to gring mine to the same length as the factory cam. On '93-'94 models, the dowel only locates the top timimg gear. On '95-newer it also drives the opti., so the front cover has a hole the same size as the front cam lobe. '93-'94 cars use a spur gear that splines into the top timing sprocket, therefore only needing a small hole in the front cover.

Many people choose to "upgrade" to a vented opti....Funny thing is, I see just as many problems with the vented optis. My original non-vented '93 unit went 94,000+ miles. Yes, I am replacing it while the engine is apart, but I'm replacing it with another '93 unit.
As a side note, though....'93-'94 units are about $100 more from the dealer.

Frank