383 vs 400

MyBlueCuda said
I've had both motors. The 400 is a dog. It was basically a de-tuned motor to keep the government happy.
I had a 1964 Plymouth Sports Fury with a 383 4bbl automatic that ran high 14:00 in the quarter that was completely stock.
Versus a 1972 Dodge Charger with a 400 Magnum automatic that ran 17:00 in the quarter bone stock.
The 400 Magnum has a real crappy intake manifold. It has an internally built in E.G.R. valve that hurts performance. On top of that is the Thermo-Bog carburetor! Never really was too impressed with that carb.
If you can find a rebuildable 60's 383 with small chamber heads I think it would be the way to go. The 400 may have a larger bore but I'd bet on my old 383 every time.

Then you had a BAD running 400, I've seen 1st. hand stock 400 long blocks with just bolt-ons & a good tune run great, i installed one in a 74 duster that came out of a 75 newport, nothing was done to it other then HP manifolds & a single exhaust, yes i said single, the engine had a very worn out timing chain, stock intake & a 2 barr., stock converter & 2.91 gears, it would fry the tire through all gears.