Looking for the best SR factory head

[Walk_N_U]

Does the SR motors have different heads.  Such as, is there difference between the a 91 SR20DE motor and the DET motors out of a DET Silvia.  And if there are any differences then which head is the best head.

[AKADriver]

There are only three SR heads that I know of.

The S13 SR, as well as the RNN14 Pulsar GTiR, B13 Sentra SE-R/NX2000, etc. have a head with long, high mounted intake ports that give a straight shot into the combustion chamber.

The S14/15 SR, as well as the B14/15 Sentra SE and 200SX SE-R, have a head with short, low mounted intake ports that have to curve into the combustion chamber.  S14/15 versions have a variable cam timing setup built in that just advances/retards the intake cam for better low-speed drivability and emissions.

The last SR head is of course the NeoVVL SRxxVE head, pretty similar to a Honda VTEC head.  It has the 'low' ports like the later engines.

There are minor differences within each of these families, but nothing worth swapping over.  The main difference in fact is if the head is machined for FWD/AWD or RWD use.

The S13 'high port' heads seem to be the hot ticket for maximum power.  The JUN 8-second Silvia uses one, Nissan's 300hp naturally aspirated touring car engines used them.  I don't really have numbers to back this up, just anecdotal evidence based on the sorts of cars that use them.  I'm not sure if it's just because S13 cores are cheaper, but they're all over the place making huge power, even in later chassis.

The NeoVVL head most likely flows the best "out of the box", but good luck getting it to work in a RWD car.  It's been done, but details are sparse.  It doesn't matter anyway if peak power is the goal, especially considering the added cost.

[mbmbmb23]

http://www.junauto.co.jp/products/cylinderhead-part/sr20det.html?en