Carbs swap + Mpgs

[stav2201]

I have a 1975, 280z that im switching over to carbs, im picking up a set of 240z SU's for right now until i figure out if i want to do triple or double mikunis or webers (or just keep duel Su's). I have a p90 head i can use but the 240z engine im picking up has an E88 head (which i understand is great for carbs). I'm curious as to which head would be better for some decent power but mostly fuel economy and reliability. Also, if running duel carbs (mikunis, webers, or SU's) is better for Mpg than triples. Keep in mind that i dont really plan on modifying the engine too much, im using a 83 280zx distributor and have no plans on swapping cams out, after market manifold is a possibility in the future and coil on plug setup.

[BlueStag]

I am no expert.

 

A '75 280Z engine will have dished pistons. If you put a E88 head on it, I think your CR will drop to absurdly low levels.

 

If you use the P90, I think the same will happen. You might want to spend some time at: http://datsunzgarage.com/heads/

 

The P90 head has to be the best head that you have on hand to use. It breathes as well as anything Datusn made for the L6.

 

But you will want to put it on a flat topped piston engine.

 

Especially for your modest power ambitions, you will find the SUs very satisfactory.

 

A pair of Hitachi SUs will supply the needs of an engine making 250hp, or so others on this board have shown to be true.

 

You have a shot at making 160hp with what you have, and your minimal goosing plans for the engine makes sense to me.

 

As for MPG, if you want to maximize that, you want fuel injection.

 

SUs are best in that: they are the cheapest carbs that you can use, AND they are idiotically simple to work with. I say that as I am an idiot and would be flummoxed by Webbers etc.

Edited March 7, 2012 by BlueStag