|
Here's a general guide to what sort of head it is (I wouldn't trust the eBay descriptions on most parts, even if it cam off a '71 1800E there's no guarantee it started off on one).
First look for injector pads - the raised, machined areas over the intake ports. If it doesn't have those, it's either a B18 or carb B20 head, and you can discriminate between those by weird 'umbrella' valve seals at the top of the stem (B18) (I'm not sure how those work, even in general theory) vs. the 'real' seals, inside the springs on the valve guide (B20).
If it has injector pads (even if not drilled out) then it's a later head, and should have the bigger valves of an injected head. Next, look at the center head bolt on the manifold side. There is a little raised, machined surface for the bolt to torque onto. If this is completely surrounded bu lower, rough cast metal, it is a B20E head. If it is connected to one and only one of the nearby raised machined injector pads with a little strip of raised machined metal, then it is an early B20F head. If it is connected on both sides to both nearby injector pads with raised machined metal, then it is a late B20F head.
If you get an injector head with undrilled injectors, it might be something interesting (like an R-sport head) or it may have just been a late production carb head replacement from the parts department. R-sport heads will generally have a stamped part number on the upper surface, in the same general area as the center head bolt, on the manifold side. They sold different flavors of the heads too, so I'm not sure what differences there would be on all of them.
From what I understand the late B20F heads are the ones with the most potential for improvement, because they used different internal casting cores, and there is more metal in the places it needs to be ported more for better flow. Try to port an earlier head as much and you'll hit air in the ports.
--
'63 PV544 rat rod, '93 Classic #1141 245 +t
|
