davepl

I'm putting together a 396 LT4 based on a '93 engine to go into a '94 car. Before 95, they drove the optispark with a little driveshaft from the center of the cam gear.

95 and later they are driven off of a longer cam pin. The optisparks and timing covers are not interchangeable (more info can be found at http://para.noid.org/~muttvette/opti.html)

Question 1:
This also means the new LT4 and GM Extreme Duty timing sets, which I already blew $250 on, isn't compatible with the 93 optispark... Because it lacks the center "teeth" to turn the 1993 driveshaft. Correct?

Question 2:
So, if I stick with the 1993 timing set and replace the chain, am I at any serious disadvantage?

Question 3:
A late cam is compatible with an early optispark as long as the cam pin is installed at the correct height. How do I change this? Do I saw the pin off at the right height, or can cam pins be removed and replaced, or pounded in further? In other words, how do I get the cam pin on a replacement cam down to the 93 level?

Thanks,
Dave

Injuneer

Since this relates directly to the LT1/LT4 family of engines, you would probably get better results on "LT1 Tech". Moving it there.

davepl

You'd think, but no replies yet :-)

Someone must have run into this before! Help!

shoebox

Correct

It would be much better to go with the more robust timing set if you are going to be spinning high rpms on a regular basis. A 95 timing cover is not that expensive and if you are in need of an opti replacement, the vented is cheaper.

Depending on the cam, you may be able to pound it in. If not, grind it down to the proper level.