I just bought a 65 malibu can i put a big block in it without having a cowl induction hood?

yes this car came with a rare option of a 396 in 65' as long as you don't go hi ris manifold.

also if you use a dual plane manifold it will fit but you will need an air cleaner that drops down 4" over the carb

cross ram low with 2x4 bbl is fine to

ALL THE ABOVE ARE CORRECT BUT YOU NEED TO KNOW THAT ALL BIG BLOCK CARS HAD SUSPENSION SYSTEMS FOR THE BIG BLOCK APPLICATION TO INCLUDE THE SWAY BAR , SPRINGS ETC... THIS SHOULD BE YOUR FIRST CONCERN IF YOU WANT TO DO THE SWAP TO A BIG BLOCK THE RITE WAY!!!

I'M NOT SURE OF THE DIMENSIONS {SIZE OF ENGINES} BUT IF A 396 WILL FIT, A 409 PROBABLY WOULD TOO. AS FOR CARBS, AIR CLEANER & MANIFOLD. ME I PREFER THREE DUECES. EDELBROCK USED TO MAKE A MULTI CARB INTAKE THAT SET LOW LIKE THE STOCK ONE. HEY YOU ARE ONLY HINDERED BY LACK OF IMAGINATION & MONEY!

Kevin Look up the z16 option code for the '65 malibu. It will answer all your questions.

you also need to change the frame mounts for the engine mounts & suspension up grades.