More on the "small FE" idea....

[Joe-JDC]

The size is not the problem, it is the shape of the port, and the awful dogleg so close to the short turn of the valve seat.  Airflow wants to take the shortest distance between the carburetor and the chamber, which causes the air/fuel to shear over the short turn if it is misshaped the least amount.  The short turn makes or breaks the FE intake port.  Get it right, and the ports can go to 320+ on the R head with large valve, and 310 on CJ is possible with larger valve.  Not easy, but can be done.  I have ported hundreds of the sbf heads, and I have yet to find one that will go 190 cfm with stock valve size and stock valve job from the factory.  JMO, but it is from my experience.   Joe-JDC

[blykins]

189 is awfully close to 190, Joe.....

[Heo]

The size is not the problem, it is the shape of the port, and the awful dogleg so close to the short turn of the valve seat.  Airflow wants to take the shortest distance between the carburetor and the chamber, which causes the air/fuel to shear over the short turn if it is misshaped the least amount.  The short turn makes or breaks the FE intake port.  Get it right, and the ports can go to 320+ on the R head with large valve, and 310 on CJ is possible with larger valve.  Not easy, but can be done.  I have ported hundreds of the sbf heads, and I have yet to find one that will go 190 cfm with stock valve size and stock valve job from the factory.  JMO, but it is from my experience.   Joe-JDC

Exactly what my headguy told me. And he put the major work on the short turn radius.
He said on my C4 he wanted to fill up the floor of the intake port  because that would
give me some gains in fuel consumption + some torque.

 And he dint like the exhaust runner under the valve were there is a "cave" for some reason.
I shall give him another set that he can go "all out" on

What is the biggest valves you can run in a 390 bore before It starts to shroud them
or hit something?

[cammerfe]

My own, off-the-cuff answer is that you are safe enough with 2.100 with most available head castings so long as you also stay with a 1.65 exhaust valve.

KS

[My427stang]

On a street engine you don't want to get too hung up on flow numbers. For a street driven carburerated engine or a mild small cubic engine you want fuel atomization and velocity. Keeping fuel suspended from idle to 3000 rpm is what gives your vehicle street manners. Take a look at the designs of the fuel injected intakes vs a carbutated intake. A fuel injector will spray a mist close to the head, given that you can see how Ford can get away with making a dedicated fuel injection head. The same large port head used on the street and a high flowing performance head.

That's certainly a true statement, but at some point you need to fill the cylinder.  Remember, at a give a/f ratio, part of that equation is air. Of course, nobody wan't to see a tunnel port 352 on the street trying to idle around, but a good fast head, prepared for the demands of the build, makes a LOT more power than a stock head with it's sharp turns and places for fuel to come out of suspension at port transition, guide bossess, slag, etc.  On an FE in particular, I'd rather see a guy "over" head and run the proper intake, than the other way around, which is generally more common

[CaptCobrajet]

A small, happy head with a properly sized manifold will ALWAYS perform better than an oversized head and/or manifold, regardless of flow bench numbers.   The 400 inch and smaller crowd NEEDS a small high velocity head with good flow, and the stroker crowd would find the results interesting even on the bigger engines in street apps.

[FElony]

A small, happy head with a properly sized manifold will ALWAYS perform better than an oversized head and/or manifold, regardless of flow bench numbers.   The 400 inch and smaller crowd NEEDS a small high velocity head with good flow, and the stroker crowd would find the results interesting even on the bigger engines in street apps.

Ain't gonna happen, Blair. I tried to make a case for a small chamber (like the '60) version of the new stuff coming out a few years ago, just for smaller FE's. Much like my pitch for a run of high-deck pistons and long rods, I was kicked in the balls and left to fight demons on the parapet. But that's another story.

[CaptCobrajet]

Ahh but it IS going to happen.  I have the ports to do it now, but to cast it, rather than mill the Pro Ports, is a short time away.  The 4.6,5.4, 6.8 two-valve mod heads flow about 250 at .500 lift.  To make street power like a V10 with a small FE, we need 1.25 times the flow of one port in a 10 cyl, to move the same air at the same cubes, so 312 cfm give or take.  It's a pet project for me.....I just have to work it in. 

[FElony]

Ahh but it IS going to happen.  I have the ports to do it now, but to cast it, rather than mill the Pro Ports, is a short time away.  The 4.6,5.4, 6.8 two-valve mod heads flow about 250 at .500 lift.  To make street power like a V10 with a small FE, we need 1.25 times the flow of one port in a 10 cyl, to move the same air at the same cubes, so 312 cfm give or take.  It's a pet project for me.....I just have to work it in.

Nah, they'll all just beat you up, tell you to buy a stroker kit, and send you emails about the stupidity of running a 6-liter FE. And there will still be the issue of pistons and rods. By the time you buy new heads AND custom pistons AND custom rods... cha ching, build a 445.

If you do that head anyway, though, test it on pump gas with Singh grooves, and make that an option. If you are going to get lynched at high noon, you might as well be a pioneer.

[chris401]

Robbed this post from another site. The engine is basically built from what the internet calls junk. Although a decent cast piston would improve petformance, mileage and power in the 352's current form there is no mention of crafty machine work or expensive forged pistons.


This 352 is a stock OEM piston and OEM 4v camshaft 66 Galaxie engine. D2TE-A heads, Edelbrock SP2P-390 intake and a Quadra Jet. Cam is advanced 4° and the carburetor could use some tweaking. The factory deck and .038" head gaskets give it .091" quench. With machine work, dished zero deck pistons it would be a responsive engine. As of now it gets 13.3 running 80 empty. It was able to pull this load up I-35 between 60-68 mph. The wind would start swaying the motor home at 70. Staying out of the secondaries it got 6.3 mpg.

[drdano]

A quadrajet!  Someone go beat that guy up too!     Small primaries and chunnel sized secondaries?!  Blasphemy! 

[chris401]

A quadrajet!  Someone go beat that guy up too!     Small primaries and chunnel sized secondaries?!  Blasphemy! 

I live in Waco TX. I am 41 with crushed nerves in the lower 3 disc. Bring couple of MIA fighters, should be about even.

[chris401]

A quadrajet!  Someone go beat that guy up too!     Small primaries and chunnel sized secondaries?!  Blasphemy! 

I live in Waco TX. I am 41 with crushed nerves in the lower 3 disc. Bring couple of MIA fighters, should be about even.

In reality it is only L5S1 the two up top are mere encroachments and you'll need to come on a rare day I feel like it. Another reality is two hills slowed me to 50 mph. Would have been ok on a third but a 50 mph drunk got in front of me. With no distance to get back up to speed everybody but a box truck passed as I topped the hill at 42.

[fastback 427]

That's pretty good performance from (junk). That trailer has to weigh close to 5000 and the motor home has to no close to 8000. What transmission and rear end gears are in the truck. Also wondering if the sp2 intake is holding power back a bit?

[chris401]

NP435 and Dana 60 4.10:1 open diff. For my use the intake is perfect. Although the engine is bacily done at 4900 rpms. My engine speed is 3000 at 70 mph where most dynos start. A tow trucks torque towing power is more important than a street/strip car/truck horse power.