john 67

I am installing a 4l80e / ls2 into a 67 chevelle .I used some cooling case fittings to convert from snap lock to 5/16" flare ,thus converting the lines from 3/8" to 5/16" .Will this be a problem cooling the trans ? the car will be used for everyday driving and some power tours .also i have not purchased a rad. yet,should i buy one with a cooler or one without and use one such as a B&M 70274? thanks JOHN