Seems like there are three production 1x4 castings and an XE one.  Probably 20 years ago I tested three different manifolds on the same engine.  I don’t think any were the XE version.  I still have the E and G but the other one is long gone along with my memory of it.  There were subtle differences in the ones we had here and they all ran about the same on a 650 hp, 416 cube engine.

SOLD

I’m surprised that I have had no one interested in these heads yet.  They are really a good deal.  I guess I will reduce the price to $2000 ready for springs, plus shipping.  Keep in mind they need to be on a std 427 or larger bore due to the big exhaust valve.  Thanks

The BBM heads are cast in South Korea in a state-of-the-art foundry, as are the blocks.  BBM is a US based company.  All design, engineering, and testing is done in the USA, and all final machining,  cnc porting, blending, etc. is done in the USA. The seats and guides are also made in the USA.  Quite different from the Chinese knockoff situation.  The South Koreans are also our friends, aligned with the USA.  I am a person who supports US manufacturing of all kinds, but casting here has become hard to do.  I had a conversation with Bill Mitchell at PRI and casting here has become very difficult.

The quality of the BBM castings is top notch, and happening.  Right now I have about 300 BBM heads.  I use and support Edelbrock also.  They have made me 30 Pro Port castings in the last year.  For me, it is hard to argue against the BBM unless we are really moving the ports.  For raised and relocated ports and chambers, I use the Ed Pro Port castings.  For “off the shelf” available heads, the BBM heads are the best heads, and they are available.  I have two guys working five days a week on BBM heads as a separate operation from everything else we do.  The only thing that isn’t done in the States is the casting and initial machine work.  Sadly, I couldn’t get 450 good castings poured in the USA in a nine month period of time the way things are now.   When Doug ran out of the old castings, we redesigned the ports and chamber, and the port and water jacket cores had to be changed, which is a big deal, but they got it done.  A 50/50 US-Korea head is 1000% better for the USA and the FE community than no heads, or 100% Chinese heads. 

These heads are take-offs from a rebuild we did.  Customer went to the next level. They are 6008 Edelbrock castings with Craft CNC intake and exhaust ports. We installed new 11/32 guides, new Rev valves 2.220/1.750, our valve job, and a deck surface cleanup.  Nice castings with no electrolysis in the water jackets.  Basically new heads again.   $2250 ready for springs before shipping.  We can outfit with springs if desired, price dependent on requirement.  If interested, email to blairpatrickfe AT gmail dot com.  Can email pics to interested inquiry.

Thanks

If you notice the low lift numbers on your stock vs the 11/32 aftermarket valve, you can see why Ford used that 30° seat and radius under it.  With the .500 lift they had net of lash, the average flow with cams of the day was way better.  The sharp corner short turn in the small F is why it stalled at the 246, no matter how far you opened the valve.  The 45 valve job caught up right about the place a stock cam was at full lift.  The flat machined chamber also likes the 30 seat.  If you lightly tuned up the short turn, put a 20° top cut on, sunk the seat just enough to get your 20 top about  60 wide, then knock the edge off with a 15, and go under the 30 and put a 54° about .030 wide to blend into that radius under the bottom, you could see 290 out of the small F at .500, and probably 300 at .600.  There ain't much room to work without poking through somewhere.  A little more short turn work and a little epoxy in the right way, and it will go 320 with low numbers pretty close to that Trick Flow you like so well.

The Big F head was something that was intentionally the same casting number to help class racers.  The NHRA tech people eventually figured it out, and gave the Big F a different HP factor and published runner volume.  153 cc versus 164cc if I remember right.

The street combo Medium Riser Small F was a mean street performer.  For what they were, they ran better than they should have, and hurt lots of feelings of the Chevrolet and Chrysler folks just because the "combo" was good.

The worst thing you can do to that head for street use less than .600 lift is cut that radius throat out and put a steep valve angle on it.

Take baby steps working on that short turn.  Too much and you will go back the wrong direction, and you can't get it back.........

To test it, you would need to do as Jay suggested and shim the thrust plate, and put the cam gear back on it and pull it up.  With no thrust plate, it will not keep the cam located while you try to turn it.  It will just push the cam until it locks up.  Try it with your thrust plate and top gear in position.

I have heads here with programs run for 2.100, 2.200, 2.220 and 2.250 intake valve sizes, and 1.665 and 1.680 exhaust valve sizes.  These are upgraded castings with my ports and updates to the original chamber design.  All intake ports are cnc’d to enable ports with different valve sizes for various applications to be used on the casting.  We have chamber and exhaust programs also, or we can do the exhaust and chamber as-cast.  High quality heads that can be tailored to fit your purpose.  Call or email if interested.  423-802-two four seven two or blairpatrickfe at gmail dot com.  Thanks