71 4dr Dart 318 w 4bbl

My 2 cents - cheap summit headers ( about $ 125 - $ 150 ). NEW cam & lifters ( under $ 200 ). The more lift and duration you can stand the better it will sound and perform. Careful! To much lift and duration and you will risk " Mopar fever"! If you over shoot the lift and duration a little bit you may have to have both feet on the break at a stop, but I thought it a small price to pay for that sound and performance:) I installed a B&M shift kit for like $40? Nice crisp shift with the occasional tire cherp under hard acceleration:) your question about the rear end? It's most likely a 7 1/4. With a four barrel and said upgrades and a led foot you'll be hearing a lot of noise coming from that 7 1/4 soon! LOL when that happens you may want to look into an 8 1/4. Way-way cheaper than the 8 3/4 that would be overkill for your 318. (So far I've cyber spent under $400 of your money on what imho was the best bang for my buck on my 72 - 318 duster years ago) By the way, nice looking dart!