I've searched and all I found were tidbits and references to any differences.
I've got a stock B18b head/block right now.
I have the opportunity to buy a rebuilt B18a head with a port and polish job.
Aside from the valve covers, what are the differences in the head, if any?
Will my B18b Skunk2 manifold still bolt on?

I'm just rying to figure out if I should do it before I pay to have the new head shipped and find out it won't work (or has to be ghettorigge).

Thanks.

 

All the parts will interchange.The "b" has slightly improved ports and cams.
Glenn

 

there are some minor differences in ports between the bare heads, but nothing to be discouraged about since it's ported. polishing isn't all it's cracked up to be, especially on street motors. PM to b!tch and moan about that statement. otherwise, the cams are smaller, the intake manifold runners are even less straight, the plenum is funny and smaller, and the throttle body is 58mm on b18a's where it's 60mm on b18b's. i think that about covers it.

 

And a silly follow up question...are the valve covers interchangeable? I have the later "flat top" and prefer it to the earlier "bumpy top".

While its not a deal breaker...I'm just trying to weigh all the issues before deciding on the purchase.

 

Valve covers will interchange between A and B.
Glenn

 

OBD-0 and OBD-1 valve covers easily interchange. OBD-2 valve cover does not [so] easily interchange with the other two. it has the PCV valve in the valve cover as opposed to on a can at the back of the block. you'll have to sort this out to use the late-model B18B and B20 valve cover.

 

i just say plug the obd2 valve cover hole and use the stock pcv port on the 18a's , or you could swap intake mani's

 

swapping intake manifolds won't really help. i don't even use that little hole in mine. it's too much of a PITA to get the rubber hose in and out of it.