I gave my 21 year old son my 70 challenger (318). We want to restore it and make it a 440 sixpack clone. What year blocks make better motors?does it matter? Are the newer (late 70's ok or should we look for a69- 70-71 block. I think he wants to build a stroker motor. Any advice or pro's and con's would be appreciated. I am new to mopar rerstoration but recently finished a 1970 Ford torino convertible with a 429 SCJ and 4 speed for myself. Thanks, Eric