I think I read somewhere that a lt1 350 block is different from a regular 350 block, my question is
Is there a difference and if so what is it?
Thanks

 

Yes, they are very different as far as water pump mounting and passages. If you look at the front of the block, it is very evident.

 

Thank you, I wanted to double check.

 

I can't remember off hand, but I believe it's gear driven, correct?? (I mean the water pump). Also it's because of the reverse-cooling that required the changes in the passages, both through the block and the heads.

LT1's would also lack the rearward distributor hole I believe (since they have the Opti-spark mounted on the front of the engine ... would they then have a reluctor ring on the crank?? or do they use some other means of crank/cam sensor?? )

 

The optispark distributor is driven directly off the front of the cam and it serves as the cam position sensor to drive the ignition. Later models did get a crank position sensor, but all it really did was assist in misfire detection for the OBDII. There is no distributor hole in the back of the LT1 intake manifold, but if you remove the manifold you can see the block still has provitions for the legacy distributor and GM uses a stub shaft to close up the hole and procvide a means to drive the oil pump. In fact, it is possible to run a conventional distributor in a LT1 if you make a hole in the intake manifold. Getting that to fit under the cowl of a f-body would not be fun, though.

 

^ ^ interesting! Good info!

 

Good article, hilighting the differences, with photos:

http://www.automotiverebuilder.com/ar/ar99928.htm