So I bought a set of bare BBM FE heads when they were on sale a few years back. Then shortly after that Trick Flow announced that they were going to be coming out with new FE heads. After the Trick Flow heads came out I watched interestingly for any reviews. In general everyone agreed that they flowed much better than the BBMs right out of the box and were of equal quality. So I advertised my BBMs on a FB for sale group and have been looking into buying a set of Trick Flows. But then I was having very knowledgeable FE guys commenting. About 1/2 say keeep the BBM's and 1/2 saying yes go with the Trick Flows. My build is going to be a 427 block based 500ci street/strip engine. Probably 50% strip and 50% street (45 min drives to work occasional in cool weather). BBM block, Blue Thunder 4V intake, RPM 4-3/8" forged steel crank, rods/pistons/camshaft/valvetrain still undecided at this point.
The TFS heads are relatively new and a lot of guys don't have experience with them yet. I think that's why you're getting a 50/50 opinion difference. If you compare OOTB heads to OOTB heads, I don't think any other head will out perform them.
On the bench here, the TFS heads hit at about 335 cfm @ .600" lift. Those are out of the box numbers....disassemble, put checking springs on, throw them on the bench and go. Keep in mind that those numbers are with a 169cc port volume. As Blair pointed out, the exhaust side is a little lacking. I think I'd have to disagree with the chamber shape as they seem to work very well and in some applications have only wanted 29-30° timing.
Also on the bench here, an unported BBM head (read as just valve job and seat blend) will go about 285 cfm @ .600" lift. Different guys prep them differently and can put more/less work into them.
FWIW, a 445 with a set of OOTB TFS heads, Performer RPM, and a 231/239 @ .050" hydraulic roller with 10.3:1 compression will make right at 550 hp here with 590 lb-ft of torque. A 445 with BBM heads and a larger hydraulic roller (235/243 @ .050") will be down 15 hp.
Now, the way I see it, you can sell your BBM heads and buy TFS heads, or you can send your BBM heads out and have them worked over. If you send them anywhere, I would let Blair work on them. I'm not a fan of some of the CNC port jobs that you seem for those heads.....you will end up with a huge port volume and I think Blair would shy away from that.
I haven't built a 490-500 inch engine with the TFS heads yet, but I have an order for one. I'm thinking that will be about the upper threshold for those heads since they are at a 169-170cc port volume, but I think they will still shine. FWIW, they will support 700 hp easily here in shelf form. I don't know of many heads that you can buy off the shelf, pull them out of the box, bolt them on, and make 700 hp.