Hi all, Could you all give the pro’s and con’s of 1967 400 big port heads? What CC are they? Are they good Perfomance heads? Is the eddy head a step up? Thanks Mikey
Out of the box they will out perform 99.9% of stock iron heads no matter the amount of time spent on them. Mild bowl work and the gains will be even more substantial Eddy head as cast would equate to lightly worked set of irons at best. They say the valve jobs are questionable also idk,..
Yeah it’s what I currently have on the 455 and compression is a cruiser friendly 8.2:1! I would like to be at least 9:1
The bowls on stock iron heads really neck down hard. At least my 73 small valves sure do. Had them done and what a difference. Cylinder head man at JA racing engines showed me before and after. Thats where power is.
The 67 Big port head is a great head for Street cars especially with cams up and around .500 lift. I have found once you get above .550 lift area the air flow goes flat and then turbulent do the flat floor design. Once you get above the .550 lift area the floor needs to come up at the short turn radius. At higher lifts the air flow needs more time to turn the corner. I used these heads all the time on my street cars.
No, I am specifically talking about the floor on the standard port. The floor is flat on the 67 Big port heads and raised on the later heads. A standard port with a raised floor is more stable on the higher lift numbers then the 67 Big port heads. This doesn't mean much to the street guys because most of the camshafts that are installed in these engines are at or around .500 lift. The TE heads raise the entire port, entire different concept.