X3,The 352HP and 390HP intakes are so similar I've always used the date to identify them,supposedly they increased the port volume slightly from 352 to 390 to 406 but I don't know if anyone has tried to measure them,it wouldn't surprise me if it was baloney.
First I’ll say if Jay is reading this thread he’s probably chuckling, because both the original question and this one would likely have been answered with a copy of his book “The Great FE Intake Comparo” lol. By the way, the book is an excellent resource, everyone here should have a copy
Jay tested a 390 HP intake and has a picture of it in the section. The one he tested even had a “1B2” date, just a month before Frnkeore’s intake, although I don’t think Jay went into detail on the date codes, but the date code is noted in the book.
There are a few unique differences between the earlier 1960 352 HP aluminum intake and the later 390 HP, I learned those when I volunteered my ‘60 352 HP intake for Jay to test for his book, and folks from the old FE Forum identified it and pointed out the visual differences. The ‘60 352 HP intake can be identified by the flat carb pad, the later carb pads are angled. Also the #5 & #8 intake runners “disappear” into the deck of the intake, the runners on the later intakes extend closer to the carb pad. And the firing order on the ‘60 352 HP intake is on the rear of the intake.
And Jay did measure the port volumes of all the intakes tested for the book, and yes the volume was increased - the ‘60 352 HP intake measured 2675 cc, and the ‘61 390 HP intake measured 2950 cc. There was also a corresponding performance increase in the dyno test.
I don’t know if anyone has documented any differences between the ‘61 390 HP aluminum intake and any of the subsequent 406 & 427 LR versions? Other than the casting number eventually appearing of course.
Here’s a picture of my ‘60 352 HP intake so anyone following this can see the unique identifying features of the early intake. The intake is also pictured in Jay’s book.
