Canfield has 2 SBF heads, the hiperf-el-stock-o's which is what the jegs more then likely are, and the race heads. I have 3 sets of the the race head and the are as pictured in the post above. The race head are a good head, making 570hp at 7500 with a fairly short duration roller. Flow on the head for the cnc race version (TEA did 2, F-P-S Did one) are all about 310-320cfg Intake and 265cfm ex. The other canfields are designed for the entry level, and fit without probabally too much trouble on 5.0 stuff. The race canfields are more of a problem as the ex port is up .400 so your header will have to be .200 higher and will not generally work with header for stock position. Nice thing is after trying several sets of headers on the 65 stang, none fitting, the custom set allowed the use of the wide bolt patter in the ex flange. It is a good thing for any car that expects to have good header and not have to deal with the PITA indent for hard to get at bolts.
Another place to look for the OEM version of the RACE head is Ford Performance Solutions in Anaheim, CA. The are branded as the 'Avenger Series' and are also good as well as a good value as long as you can stand the engraved 'Avenger' that they put on the front of the heads.
I have to get off the coffee!
Sandy
Forgot to say the motor is a 331