Mn47 dished l28 setup

[silver280zx]

So the other day i bought an mn47 head, and i was wondering if it would be ok to run the head on an l28e bottom end with dished pistons, running a p79 cam. Would i get and gains over my stock zn47 setup? For the mn47, i plan on doing a mild port, and leaving the smaller intake valves, the only thing im worried about is running lean. This should put me around 9.5:1 compression with a 1mm head gasket right? also, i have a 460 lift 280 duration @ .050 236 duration at .025 cam sitting in the shop, and I was wondering if it would be a waste or not to put that cam in the mn47 running stock valves, and efi. Thanks for the input.

-Tyler-

[primer&rust]

I'm running a mn47 shaved .050", with porting, and 44mm intake valves on a dished piston L28. It runs good and strong although I need to change the valve timing a bit (it's not right on). My car has a stock Z camshaft and now like to run on premium gasoline. You can notice less power if you use regular gasoline. Your set up should work great in my opinion.

[silver280zx]

Awsome, thanks. Do you think the larger cam would benefit it even more, or would that be a waste of time?

[Xnke]

To answer your questions, run the high lift cam, port the head, and get the valves changed. If you don't do all the above, especially the valves, you may actually lose power...But if you do all the above, you will undoubtedly make more power.

[1 fast z]

My MN47 ported heads, out flow most ported P90 or any big intake valve head, with me leaving the stock valves. Keeps the port velocity up also. What most people dont understand, is that to take advantage of the bigger valves, you ALSO need to install bigger seats, or do alot of machining.

[bernie lomax]

if no port work was done on the MN47 head & the stock valves remained, would the stock MN47 produce noticeable gains on the stock dished piston L28E? sounds like putting in the larger valves is spending money that may not be necessary if low-mid range torque is desired...appreciate your time

[silver280zx]

So im still waiting to see what i want to do, the maxima head would put me at 9.2:1 compression on the stock bottom end, and I was thinking that 280 duration cam would a little much. Any other thoguhts?

[2eighTZ4me]

A reknowned ITS racer friend of mine staunchly believes in leaving the smaller valves in his old E31 heads, as it increases flow velocity, and not so much volume. He's won many championships in his class over the 30+ years of racing / building he's been doing. I kind of trust his word.

 

I left the stock valves in my MN47 (had a bunch of port work done though) and it has plenty of giddyup...