Trying to gain a few hp. I have aiready swapped the flat tops(carbs) out for round tops. Would like to go to a 72 E-88 head and a stock 260z cam or a stage 2 cam. Also change the exhaust manifold to a 72 or add a header.Also replace the timing chain. Hoping to gain about 15-20 hp.Is this possible.

Use the early E88 head, install L28 valves and seats, then bore it out .040 inches, use an Isky Stage III cam and you should pick up 15 h.p. or even more.

72 E88 - milled a few thousands to make sure it is straight/flat and increase compression slightly..

L28 valves/seats

Mild Port Matching {no need for polishing}

Use the 72 exhaust manifold {headers only add heat/noise unless you do significant rework on the head, add cam's and free flowing exhaust - for that matter the free flowing exhaust will add more than the header}.

Diseard's Cam

70-72 SU's fine tuned [you can pick up about 3HP if you leave the air filer and cover off for track events}

Electronic Ignition with good wires

Most "stock" but good running L24's in the 240Z's will put down around 120HP at the rear wheels. So do a chassis dyno run before you start changing things. Then do another run after - that's the only way you will know if it was money well spent.

Yes, 15HP at the rear wheels should be possible if the engine is property tuned..

FWIW,

Carl

Oh.. BTW - if you change cam's and timing chain - make sure the cam timing is dialed in correctly. If you are having a shop do the work - ask to watch that process being done.

Edited July 4, 201410 yr by Carl Beck
Added note about dialing in new cam timing

Tune - tune - tune

Dyno before , then after like Carl said.

I got 155rwhp from my L24 with SU's and all of Carls suggestions.

Seems like an N42 or N47 L28 head would be a good choice. It already has the bigger valves and essentially the same combustion chamber size. Isn't it about where you end up after modifying the E88?

I believe that depends on what e-88 head we are talking about.

An early e88 with bigger valves will down around 41.5. The earlier head will not be a fully OPEN chamber like the 42 or 47 head.

I just wanted to write something so I'd get the green arrow. This is great!