My 1970 CST 402 BB has the stock Roch. carb beyond help

[bookemz9]

I really like what this site and everyone involved has done sharing their knowledge and experiences with likewise vintage truck lovers. Please bear with me as this is my first attempt at writing a post. Please let me know if I am not doing things as to protocol. I own a 1970 CST with the 402 big block and turbo 400 my dad ordered this truck new to haul his 5th wheel around the country the glove box door was almost not big enough to hold all the options decals so from an early age I knew this truck was going to be mine. After my dad raqcked up 327000 miles he parked it when he heatd the first hints of a rod knock to keep any damage minimal it sat almost 2 years before funds were available to fix it.all this time I'm doing anything I can to try and buy it from him the truck was still as new and meticulously maintained. He didn't cut any corners in the rtebuild either he spent 2800.00 for a professional rebuild by a well known local who did an excellent job.after break in and the local station rebuilt the stock rochester 4bbl carb things just worked my way I have ten other siblings with at least half of them showing an interest in the truck . I ended up with the truck because he knew it would never be sold or in need of repair and would always be reliable when he needed to borrow it so for the sum of 3000.00 I was a happy new owner. I am a painter by trade and have now owned the truck for 10 years and I've put on almost 6000 miles since they were costly miles due to the fact the carb was worn out prior to rebuild I wqs lucky if I got 6 miles per gallon it was dunping the gas as fast as it could in fact at one point I had a fire under the hood luckily I caught it befure any damage occured biut it scared me enough to know I need to fix it also I have never been able to enjoy the power of the fresh big block.This is where I Am reaching out for experienced information on the best way to obtain the extra horsepower I know Ive been missing. I have had all kinds of motors but this is my first experience with the 302 I have acquired an almost new holley 650 cfm and would like to know if this carb would be suitable for this motor and what manifold should I pair it up with I dont know for sure if ihe heads are square or oval port I gfelieve they are oval but I would rather take the word from someone with experience I am on a budget so I was hoping that I could get away with a used manifold and if so what are the negatives I should look for if any that could be problematic down the line. I also have access to a new in box edelbrock 600 performer carb if I could mate that with a cetain manifold I am open for suggestions I know with the right combination I'll get power I should have had long ago. Thanx Bookemz9: