Important if you run D-H/S or SA

[Paul Precht]

Originally Posted by David Lee

I am building a 67/68 cuda right now and to answer your question I bought two 340 dealer replacement blocks and have them sleeved down to a 318 bore. I plan on doing my own short block and have shane studley do my heads.

And I have heard that aftermarket blocks get a hell a lot more hp than 5.

David, it would be a good idea to fill them also. A stock 340 typically has about a .100" thick wall and if you run it as a .060" 318, you'll have approx .135" which won't break but it won't make great power either. A lot of aftermarket blocks have about .300" walls.