Thread: SBC 400 needs to wake up a bit

Tweet

Hello everyone, new member here. I have a SBC400 in my Kingswood Impala that has 53thousand original miles on it. Unfortunately it has the two barrel carb and intake, so it is in need of some upgrades. I have a quadrajet off of a big block 425 Cadillac engine. Will it swap over ok after i get a new manifold? I know that they are setup different for various engines however i was hoping someone could tell me if it is viable. Being a poor college student, i will probably buy the cheapest 4 barrel edelbrock i can get at Kragen. I saw one today for 50 bucks. Good idea or bad? I am not looking for insane power out of this engine, it just seems to be a dog right now. Headers and an electronic ignition are also in the future. Any and all input is appreciated!

Thanks

Rory

You'll have a lot less hassle if you find a Q-jet off a 400. Jetting on a 425 is probably off enough to cause some poor running qualities. It might not, but tuning it could be frustrating. 400's are common enough in the wrecking yards, most have 4-bbls. If you want to go the cheapest route, grab the intake too. At stock 400 revs, there will be little difference in power compared to an aluminum intake, and it may even run better, especially when the engine is cold in the morning.

Well today i got motivated and began the swap. I found a performance edelbrock aluminum intake on craigslist five minutes from my house for 50 bucks. Pulled the two barrel manifold and carb, cleaned up the gasket surfaces, installed new gaskets and the manifold. I am going to put the carb on tomorrow. If the Rochester Quadrajet does not work, i will find one from a 400. There seems to be a lot of quadrajets on craigslist. Any thoughts/opinions on the performance manifold? I have been a diesel man all my life so i am new to these gas motors. So far i love them tho

Most aftermarket intakes are good, except the SP2P, it was a stock designed intake made from Aluminum, no performance gains goin to this intake except it is lighter. Stay away from single plain intakes, you'll lose power.
Quadrajets are hit or miss, some good, some bad. If you get a good one, you are good to go for years. A messed up one is a headache, even after a rebuild. Holleys and Edelbrocks are easier to work on, that's why so many people ditch the quadrajet. If the qjet you have works good, stay with it. I like Holleys, but Edelbrocks get better mileage.