Try an Edelbrock Performer intake. I have a Holley 4BBL on my truck but they are not a good off road carb due to the design of the float tanks. A 4BBL can actually give you better gas milage if you can keep you foot out of it most of the time due to smaller primary. You need to decide on the carb before getting the intake due to the fact that there are differences in the carb designs.
Actually changing it is not difficult at all. On a 302, you don't even need to remove the distributor. Just unbolt the intake manafold, clean off the old gasket material, add new gasket and intake, and bolt down using a torque wrench and the correct pattern and proceedure.
Some carbs will need an adapter kit for the transmission kick down and throttle linkage.
Good luck,
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