EXHAUST BREATHING for FE's ?

[FUNFER2]

A guy told me that FE's (and maybe the side oiler as well) needs a lot,.....of exhaust breathing, similar to the Hemi's. Why is that ?

[undy]

Ford FEs and the original Mopar Hemis are on the opposite ends of the spectrum. The FE (427s included) are dump truck motors. (Nobody get their panties in a wad over this, I love mine) Their OEM heads flow terribly and build great torque but not too much on the top end. It's torque that's the FE's claim to fame. Too big of primaries is the killer of low end torque. The Hemi, on the other hand, is a "top end" machine. It has tremendous flow capacity in their heads. It will benefit well from large primaries.

Having said all that, I wouldn't place much value on what the guy said...

[Mdman352]

Getting the mufflers out of the side pipes does wonders for the performance.......and hearing loss

[347stroker]

Mdman are you going to Lowes in Bel Air tonight?

[FUNFER2]

Yes, the early Hemi's are top end motors and the FE's are TQ monsters, but why do the OEM heads have such terrible exhaust flow numbers ?

Was this on purpose to create low end torque and not go for top end hp like the Hemi or are they just designed badly ?

In comparison,......how about the differences between the Pond and the Edelbrock heads ? Are they designed differently for more flow for mid & top end TQ & HP or the same as the old heads ?

Is it just the small size of the valves, or there's more to it like the intake & exhaust ports?

[brandx]

It seems that if memory serves that dump truck is not the proper term. Didn't Enzo call them water pump engines? How much top end hp do you really need?

[FUNFER2]

HP is not the question, it's design & flow.

[undy]

Kev, In the late 50s when the FE evolved from the Y-block it was targeted for heavy, full size cruisers and and pickup trucks. Torque was the requirement of the day. That mandated small ports and valves were great for low RPM torque. That recipe served well for irrigation pumps and old-timey dump trucks too. The hemis, they originated around 300 ci and always were dual-quad high winders. They were also placed initially in full-size cars but... their honker ports and larger valves were the recipe for high-winding excitement. So, yes, it's pretty much the hemis head design and increased flow capacities. That was the major diffierence.

brandx, you're in the wrong thread... Their's three others that deals with not enough, too much and simply rediculous. That was never the question here.

[jwoodard]

I don't think it's only exhaust breathing, but overall breathing. Thus, bigger valves, improved flowing through the head passages and less restrictive exhaust all make a difference. Engines are basically air pumps and removing as much restriction as possible improves flow and thus performance.

[olddog]

The FE started at 331 cid. The 352 FE is the same bore and stroke as the 351W and 351C and it compares very well to the two 351, even the 4V 351C.

There were many heads that went on the FE engines. They are not all the same. The tunnel port heads on the 427 held their own against the 426 Hemi on the Nascar tracks, even though the Hemi design has quite an advantage. The FE has quite a good record in racing.

Not all FE are the same and to lump them all into one group is silly.

As for the early Hemi designs (there were many) in the fifties. A lot of them had 2 barrel carbs. I do not recall any of them coming from the factory with two 4 barrel carbs. They made good power for what they were in their day. The 392 was very popular for a while. The 426 dwarfed them, and they were soon all but forgotten.

[joyridin']

The 1955 Chrysler 300 was the first dual 4 bbl engine. It had a 331 cuin Hemi. The next was the 1957 and 58 300's. They had the 392 with dual 4 bbls. They even had a fuel injection option.

DeSoto had a dual 4 bll version also. but I don't recall what size or year it was offered.