531 vs 405 Head

The 531 head has a few 'nice' benefits. IIRC it has bigger sodium-filled valves as standard, has larger cooling jackets and passage holes, different combustion chamber shape, better flow, etc.. Turbo addition junkies swear by it because.... ???

Anthony Hyde's page details much more... http://people.physics.anu.edu.au/~amh110/Head/cylinder_head_531_530.htm


Would it better for your 84? That all depends on what your plan is for it. If staying stock, probably not significant. If going for a power rebuild, then probably.

Others will have their thoughts on the #531 head :-)

What does it cost to get a head reconditioned? Just trying to weigh it all up? Is it worth getting another head/reco or putting the same money into reconditioning/upgrading what is already on the car?

Edit: eventual plans might call for more power. Short term will be manual conversion. I have a k cam to put in the car, and am thinking that I might as well organise some other work to the car while that's all getting done. Eventual plans might take me down a turbo route, but I'd love the car to be more fun to drive. I have the handling down, but not the go :)

Define reconditioned? A simple clean up and replacement of original re-lapped valves is about $80 here in Taswegia, but a rebuild with new valves, performance in mind, well $$$...

If you are not looking for significant gains in performance, stick with what you've got. If your working towards a more powerful motor then I can't see it hurting.

Again, there may be others who have run the #531 head on a standard motor, so their input will be richer than mine...

Cheers guys :)

I get confused easily with these things. What engine is in my 84 GLE? What is the type of injection? K jet? Is mine the 405 head?

Sorry for the noob questions, I am a noob lol.

From memory 1984 was still 2.3 B23 LH-Jetronic 2.1 with M46 4-speed with Electronic Overdrive 5th or Auto AW70

There _should_ be a casting number on the side of the head with the last three digits _usually_ giving you the head number, like this...



Others like @Angus242164 @Spac will chime in with more detail/corrections so be patient as their knowledge is encyclopedic and god-like ;-)

84 GL or GLE is B23E with K-Jetronic and AW70 or M46. No idea what cam.
84 DL is B21A with an A cam and Stromberg carb and M45/M46 or AW70 depending on how the car was originally specified/optioned.

I'm a long way from being prepared to put money on it, but I think the 1984 K-jet cars will have a 398 head, while a carby car will have a 160 (this is based on a very small sample group and may be miles off).

There's no argument that the 531 is the best, and the 405 is the second best. From what I've seen/read/know, if you rate the 531 as 100%, the 405 is 90-95% and the others are down around 70% (number plucked from my bottom, and not to be taken too literally).
The main difference between the 531 and the 405 is spark plug location, apparently. The others have significantly poorer ports, particularly the exhaust port.

Realistically, a 531 isn't usable on a K-jet car. If you've got k-jet, then look for a 405 from an 81/82 (83?) 240 or a GT (and maybe others).
My heavily worked 405 gave the highly experienced head porter a big chubby - once worked, they are exceptional heads.
I think the 531 hype is excessive, TBH.

A stock 405+K is significantly better than any stock 84 combination.

Exactly as Spac said. Spark plug location is the key difference.
Usually they demand a high price which is a bit excessive.

Thanks guys, and in particular Spac for the information. Sounds like a 405 head is what I'm after.

Bit of a side track but, 531 heads are not that rare in Australia most 940's and late model 240's have them.
That would be the most common source.. They are setup for an NA so no sodium valves.
They have a larger combustion camber than the 530.