This is the old-school way of modifying an A-series head






A12 beat the A14 for road racing. For more information see Pitroad

I could be wrong here but any chance that is actually an oval port head reworked to a large round port and semi downdraught (as much as material permits it to be so at least)?

Yes, I believe so since it has 3 small water ports not a GX head. Maybe an A14/A15 head or maybe an A12A/A13 head. I really can't make out what the page is saying

Whatever they've done to it, it is darn impressive. I haven't looked at that page in years, but I think they were saying it was producing something like 180ps (which is near enough to 180bhp in the old money I think) from 1300cc. I wonder what they might extract from an a15 with similar treatment. Maybe not quite the same hp per litre, but the peak power would be interesting to see.

Its a funny thing Im learning in Japan, the stuff online seems
to be for the consumer but the racers use their own version of
combustions chambers to get more from these ports.
If everything is available to the privateer then big wigs lose
Nissan did the same with the FIA heads intentionally made things
hard for the privateer to beat the guys making them.

I believe there is secret squirrel stuff in the A series Pitroad practice
in not showing they use popular aftermarket pushrod v8 style chambers like
the ones below
http://www.lsxtv.com/news/frankenstei ... r-all-out-ls-performance/

supposedly the A series chamber produces too much swirl for extracting peak hp and since v8 2v chamber development has way more up its sleeve, I wont be surprised this is what they are using.

Jmac prob could chime in here and I also noted an L series engine built by a skilled head porter he recommended to me used the david vizard style 2v chamber used on most aftermarket chevy and ford heads with good results for an otherwise L series novice - albeit with the help from L series gurus combined with his V8 background.

The hours that goes behind these heads to get them to make 130hp per litre is well beyond the skill, time and budget of most peeps.

chev chambers have been all the rage for about 10 years now in L series and all sorts of other 2v engines - not exactly secret squirrel stuff.

oooh I would love to do a weld up and do this to the spare head.

Don't think you can. That head is a crossflow, so rotating the valves is do-able, but on the A-series the exhaust ports would never bend around that far?

One thing that could be done is to weld up the heart-shaped chambers then grind back down into a pinched shape, like Tony Knight demonstrated on an L-series head

Cylinder Head Work by Tony Knight

oh dam you know about TK?! he's a genius on the engine work.

Thats the one DD should have posted this pic below of the non crossflow chamber. Didnt want to mention his name as he is not in datsuns usually and not for dreamers on the phone, he just does the job within the budget he works out with the customer etc. Got just over 560hp for a friend using all cast iron hoeden 5ltr. He has achieved amazing hp from that engine 237hp ate at 7800rpm and that was short of time as customer needed to get it to a rallye. In the states the most L gurus have made usually made is 215hp ate. Bas also uses this style of chamber for his Ls supposedly. Makes me wonder if these chambers work just as well for better boost numbers than H89 chambers? Maybe Jmac, Simon or Harry know or have been thinking of going this way for their builds?





here are the improved hemi chambers with supposedly unmatched compared to other heads