I assume you're talking about an Olds V8, but which one? 215, 260, 303, 307, 324, 330, 350, 371, 394, 400, 403, 425, 455, etc.......
I was told by a Cadillac Expert 59 -62 Cad 390 manifold will bolt up to 331 , not sure if Olds of those years will, I was asking because I was thinking about updating from Rochester Quadrajet to Edelbrock , AV2 the Edelbrock won't bolt up to the 331 without a hokey ass adapter, but if you change to later carb the stock Cad air cleaner will not fit without modifications,nothins ez
I wouldn't waste my time. They share a bell housing pattern and flywheel but that's about it. Any 62 or earlier 365 or 390 intake will bolt on and you can make a Studebaker intake work in a pinch. To adapt it you'll basically have to replace the mounting flange. If you're going to that effort just build it from scratch. Imo Sent from my SM-G950U using The H.A.M.B. mobile app
You could probably use a manifold from as early as 57 since that's when the AFB came into use. What year 331 are we talking about? They were running 2bbl carbs 49-51 and weren't very high compression.. You could be overcarbing it.
I have a 1950 331, so I’m mainly wondering about early 50’s Olds engines and how to make a 6x2 log manifold work on my 331 Cadillac
Maybe this old thread will help. https://www.jalopyjournal.com/forum/threads/vintage-cadillac-331-365-390-hot-rod-intakes.182391/