Changing out 318 to 340 on 73 Dart Swinger

easy swap... will need the 340/360 motor mount or modify the 318 mount to work.. a stock 904 may not hold up to 400 hp but that 904 can easily be built to hold up without anything exotic put in to it.. like stated already the 7 1/4 if thats what it has may not live long. but if you don't put slicks on it you may be ok for a while until you can upgrade. you can also drop a 360 in just as easy as a 340. only thing you'll need is the B&M 360 flexplate..