best cylinder head

[chris frizzell]

hi all just a quick question got a 280zx engine in my 280z with a p90 head .nearly finish putting it on the road but my next project is to inprove the engine .so my question is which is the best head to put on it as i want to port and polish it and a possible cam change. dont want to go down the path of new pistons as my spanner skill are limited and dont feel confident to do a full engine rebuild . unless someone knows a engine rebuilder any advise greatly apprishiated chris

 

[jonbills]

hi all just a quick question got a 280zx engine in my 280z with a p90 head .nearly finish putting it on the road but my next project is to inprove the engine .so my question is which is the best head to put on it as i want to port and polish it and a possible cam change. dont want to go down the path of new pistons as my spanner skill are limited and dont feel confident to do a full engine rebuild . unless someone knows a engine rebuilder any advise greatly apprishiated chris

Chris, P90 is a great head but Chambers are large so compression won't be very high without a lot of welding or material removed and compensation to take up the chain Slack.
There's lots to read out there.
This one Is a good start:
https://www.viczcar.com/forum/topic/4286-overview-of-l6-engine-heads/

 

[chris frizzell]

thanks for that still a little puzzeled is the N42 better ? and would i have to change the pistons or just have it machined to get better compression . i dont know a engine builder to do the work thanks chris

 

[jonbills]

What pistons have you got Chris? Flat top or dished? How much are you looking to spend?

 

[richiep]

Most of the heads have pros and cons depending on the usage and performance profile one is looking for. Certainly, if excluding the US-specific heads with the exhaust liners (N47, P79), there isn’t really a “best” head. They can all be made to kick ass, just with varying levels of work and expense to get there.

Easy answer: as Jon says, P90 is good. It has a lower compression design as standard however, given the depth of the combustion chambers. The usual way to address that is get it skimmed 2mm. Take up chain slack via cam tower shims (either stack the commonly available ones or use Kameari ‘s 2mm thick ones). Port match to typical intake gasket, unshroud chambers etc.

Above is the simple, scratch-the-surface version. Do lots of reading on the specifics!