So here is the background on my sammy bought it for 400$ and have put a lot of work into it.
Current engine setup: fresh 8v 1.6 with 32/36 with stock redline jetting for the 1.3 2 piece adapter non ported intake, stock 1.3 exhaust manifold and cat stock muffler and pipe all the way.

The questions.
Is it worth it to open up the intake to match up better to the weber's oval shape. Also if I remember right the intake runners can be opened up slightly to match the ports on the cylinder head. Is it worth the time and effort to do this? MPG or power improvements?

Would it be a good investment to get a header and run larger exhaust no cat or possibly a high flow one. I would imagine the 1.6 breathes harder than the 1.3 and might benefit for some free flowing exhaust?

Also ignition timing is currently set at the specified 10btdc anyone advance it safely? It is currently not pinging or having any heat problems.

It currently drives great and has ample power its lifted on 3'' springs and now has 235 75 15 tires. It currently gets around 20 MPG I am mainly interested in and modifications that would help out the MPG, and im aware that my lift/tire combination has an adverse affect on the MPG, but its looks too sweet to change now 

I sure love the little samurai, you all have a great site and a good community that I'm happy to be a part of. Ill include some pics of the current setup just to give you an idea of what I'm working with.

It currently drives great and has ample power its lifted on 3'' springs and now has 235 75 15 tires. It currently gets around 20 MPG I am mainly interested in and modifications that would help out the MPG, and im aware that my lift/tire combination has an adverse affect on the MPG, but its looks too sweet to change now 

That's way to low MPG for your setup.   Back when I had 2" of lift and 30" tires i still got  24-27MPG. I would take a look at that weber.

I have a 1,6 with a corolla carb and I still get 20MPG with a 6,5" lift on 35s!

it may be that your ECM  needs the caps changed out??? 

hmm dont exactly understand what you mean. "caps" like distributor cap?, ECM? does my current setup even require the ECM?

hmm dont exactly understand what you mean. "caps" like distributor cap?, ECM? does my current setup even require the ECM?

Disregard the ECM comment, they didn't see the picture with the weber or read the part about having a carb. Definetly pull out your cat as an 'open loop' system like a carb will most likely not work right and eventually clog it. As for mileage, I think you're in the ball park. I've run Samurai on 30's with webers for a long time and get between 18 to 22 mpg. There's a gas poll that'll give you some sort of expected mpg curve in the beginner sub-forum.

http://www.zukiworld.com/forum/technical-discussion-beginner-repair/what-economy-(mpg)-are-you-getting-mpg-poll-added!/

On your MPG calculation, did you verify your speedo? Tire size changes coupled with Samurai speedometer inaccuracy can really change the MPG that you 'think' you're getting.

As for port matching, definitely do the one from the carb to the intake. I was a little confused in your post; you are running the 1.3 manifold, right? Match that original carb flange to the 'adapter' and the weber. A Header and 2 or 2 1/4" exhaust will help, at a minimum, get rid of that cat... Block off and/or pull the vacuum to the EGR too.

Hope that helps.

-Eric

I used to use Webers for years on street screamers, but never had success running them in offroad 4x4 applications, LOL

Port matching is essential or the lip created by the mismatch will create a air dam restriction that is 2 to 3 times the actual lips size, think of how a eddy in a river produces an area of backflow.

A good header that is wrapped will work wonders, along with 2" ID mandrel bent tube.

You can still run a cat, they are not all created equal. A spun mettalic core cat provides very little restriction if any at all, the ceramic core cats use a monolithic ceramic block that light can barely pass thru, while you can look thru a mettalic spun core and read the newspaper thru it! On my Honda K20A2/Z3 frankenstein engine I actually made at least 8% more whp and torque thru the entire rpm range other than the very top end which was unchanged compared to running no cat and with some areas seeing up to 27% more power than when running a ceramic cat. The main problem will be reduced life if you run rich all the time.

 Do you use this for a DD or street driven and have to pass any emissions test or inspection?   

yes I am running the 1.3 manifold and I will hopefully soon match it to the webers adapter at least from what you all said it seems pretty essential.

Its somewhat of a DD maybe driven 4 days out of the week. My current exhaust setup is basically the complete stock system from the samurai, so you think I should definitely cut the cat or go to a high flow style cat? I live in kansas so no smog testing here.

It smells pretty rich, like I said I have not changed any jetting from what redline sends out factory, is there any way to tell the A/F ratio without a wideband O2 installed.

Also EGR was blocked off already.

I am putting the percentage of the larger tires into my calculations I think I'm doing it correctly.

Any ideas on timing? when I first put the engine in timed it by ear (didnt have my timing light handy) and once I finally got a timing light on it I was at about 15 BTDC. I then set it back to 10, but when set at 15 it started much faster and didnt have any detonation issues that I could hear under load. Although I certainly don't want to "push it" and start burning things up.