I’m new to building cars. I have a 1974 Dart Sport which was originally a 318 and is going to have a 440 put in it. I have never done any major car work before this so it is definitely a learning experience.
The main piece I have to get is the rear end. I’m looking for a moderate setup with decent highway cruise rpms. I’d appreciate any advice. I’m not skilled in the building and funds aren’t an issue to have one professionally built.
if the car originally had a 318, theres a chance there is an 8.75 rear end under it already, although it may also be an 8.25.
when I got my '73 Duster, it had an 8.25 rear under it with 4.10 gears along with a mild built 440/Auto combination. it has proven surprisingly stout, although as I said, its a pretty mild 'motorhome' 440 with the primary mods of an intake and some headers. I banged on it pretty hard at times, always expecting it to go bang! at some point.
that was many moons ago and its still under there motoring away.
take a look under what you have in there already. if it has a removeable cover, its most likely an 8.25. as long as you don't hammer the thing too hard, they can survive pretty well.
If it has no cover on the back and is mostly round, its most likely an 8.75 and should hold up pretty well as a cruiser rear as it would likely be 3.23 gear ratio. its also substantially stronger than the 8.25, so you can have a wee bit more fun with it before creating a problem for yourself.
while installing a big block into an A-body isnt HARD, you will want to do your homework for some things that can trip you up. take a look at the tech pages and give it a good once over. specific oil pans, exhaust systems, engine mounts etc can be a pain if youre not prepared.
good luck and feel free to ask questions. we love seeing first timers do well.
Thanks for the info. I do believe it’s currently has a 8.25. I definitely want to go with the 8.75. I’d rather play it safe if I decide to go bigger in the future. I’m aiming for 3.55 gears maybe 3.73 for now, nothing crazy.