I am pretty new to the FE motor. I have mine setup as factory with (finally) a good carb tune through a Motorcraft 2100 and good timing through a pertronics ignition. It basically runs out of breath at 4100 or so and truthfully peaks about 3500. It's not a hot rod, never going to be. Just wondering if this is about what you guys are seeing out of good running stock motors?

I have thought about swapping out for a 4 bbl, but realistically I am not going to use the performance (whatever that might be with stock exhaust and driving all four wheels full time) and I love how well it starts, runs and drives with the 2100 at the moment.

And yes, it is a 390 even though its a highboy, the owner swapped the 360 for a 390 from a late 60s Galaxie at some point.

 

I get a few more RPM out of my stockish 390 but, not a lot more. I have headers and a fairly free flowing exhaust system, which is one of the things that really help the FE's to breath. The stock manifolds are notoriously restrictive. They can be made to spin faster but I use my truck for a workhorse and don't feel I need the higher R's.

 

 

To me, "runs out of breath" doesn't mean the engine won't rev any higher, but power production feels like it fell off a cliff. I am going to assume that's what you meant ,too.

Back in the day, most engines would hit a wall at between 5,000 and 5,500 rpm. On some it was the points were bouncing, on others the hydraulic lifters were pumping up. This was okay, because most engines from the golden years wouldn't stay together over those rpm levels.
Your 390 should fall in this category. If it stops pulling hard at 4100 that's a prime example of too small carb or too small cam. On your engine I'd put a 750 Holley. I'd choose Holley because parts are everywhere and people who know how to tune them are available.

 

 

Yeah, it seems more air/fuel related than valve floating, plus it runs perfectly fine afterwards and while I suppose it could be lifters or valve springs, the engine rebuild is supposed to be fairly fresh, and looks like it from the condition of the oil valley. Have not had the valve covers off yet though. someone put them on with a ton of RTV!

Thanks for the comments. I'll check the valves and think again about a 4 bbl.