Often, our beloved 6 cylinders are compared to V8's. Normally this is in regard to towing superiority with usual comments being that the 300 [4.9L] pulls better than 302's, especially at low RPMs and that it takes a 351 to be close to a 300. Everyone recognizes that the V8s provide more HP.

Okay, my question is: How would this comparison be if everything was stock EXCEPT that the 302 and 351 had a Carter YF [single barrel] carburetor? This is opposite of the direction most threads take, where we change manifolds and upgrade to 2 or 4 barrel carburetors.

Abandoned Bronco, I know you and F250 Restorer frequent the Ford Six forum and FTF [retired Ford Engineer involved with the 300/4.9L development] hangs out there... you might want to ask this question of him.

Looking forward to everyone's opinion.

 

Simple enough to do the comparison...using a1v/2v adapter mount the 1v carb on the 302 or 351, drive it and post the results.

 

LOL, I doubt a 302 or 351 would run very well with a YF sitting on top. 3000-3500 RPM would be about all they could reach under even a rather light load, much like a 300......

 

That'd be really interesting to reverse the carbs. If I had the adapters, I'd talk my brother into letting me try it on his 351.

Just doing some math here.
Using the typical carburetor cfm formula:

CFM = (Engine CI * RPM * VE) / 3456

With the 300, and around a typical 80% V.E., the stock 1bbl usually runs out of breath around 3000 RPMs.
CFM = (300 * 3000 * 0.8) / 3456
CFM = 208

(I've heard it figured around 190 - 210 cfm, not really sure).

The 302 would stop breathing right around the same RPMs, since it's pretty much the same CI.

The 351, however: (reversing the above formula)

RPM = (CFM * 3456) / (Engine CI * VE)
RPM = (208 * 3456) / (351 * 0.8)
RPM = 2560



A stock 1bbl 300

122hp @ 3000 RPMs (214tq)
255tq @ 1400 RPMs (68hp)

A stock 2bbl 302:

140hp @ 3400 RPM (216tq)
250tq @ 2000 RPM (95hp)

Considering it has less torque than the 300, it has less hp at the same RPM. So, around 3000 RPMs, the 300 would have it's stock 122 and I imagine the 302 would be around 115 - 120 or so. In the end, the 300 would win at most anything because it has the long stroke behind it.

A stock 4bbl HO 351

210hp @ 4000 RPMs (275tq)
305tq @ 2800 RPMs (162hp)

It'd still be making a lot of torque around 2600 RPMs, probably around 285. Since that's where it stops breathing too (with the 1bbl, it'd probably make it's peak tq and peak hp at the same time). Around 140hp or so.
Either way, it's still all around higher than the 300, but definitely by a lot smaller margin.


That's just playing with numbers. There may be other factors, such as air flow through the carb itself, that come in to play with a larger engine.