258 1BBL upgrades?

[Sasquach]

Any sugestions on making a AMC 258 i6 / 4.2l w/carter YF run better?
Motor has 74,000 miles, head reworked at machine shop with deck milling and valve work, PO installed new replacement YF. I have TFI ignition goods coming and am thinking about how to go about making this thing run right.
My intentions when I started my rebuild was more of a restoration than anything but now find that it needs to be more driveable, I will be towing this thing behind my camper and just exploring old mine roads and such while camping- will not be rock crawling or anything too serious.
Fuel injection? Dif. cam?
Thanks in advance for any input.

 

[IOPort51]

It would be a question of what you could pass an inspection with. Do you have an air injection smog pump?

Any sugestions on making a AMC 258 i6 / 4.2l w/carter YF run better?
Motor has 74,000 miles, head reworked at machine shop with deck milling and valve work, PO installed new replacement YF. I have TFI ignition goods coming and am thinking about how to go about making this thing run right.
My intentions when I started my rebuild was more of a restoration than anything but now find that it needs to be more driveable, I will be towing this thing behind my camper and just exploring old mine roads and such while camping- will not be rock crawling or anything too serious.
Fuel injection? Dif. cam?
Thanks in advance for any input.

 

[Sasquach]

I Knew I left something out. This is a Ca. vehicle and must pass smog, it does have all smog equipment on it now pretty much as it left the factory.

 

[CJ777]

I'm a ca. guy and I just installed a motorcraft 2100 2 brrl in place of the 1brrl carter. It runs and has increased the drivability so much better. It is also supposed to pass emissions even better than the 1 brrl carter. Fuel injection would be the way to go though if your willing to spend the dinero.

 

[Sasquach]

Thanks triple7, What did you do for a manifold? new or salvage?
I was a little shocked to see the YF on my AMC 258 i6 / 4.2l when I got it, have the same carb.(I think) on my CJ3b 4 cyl. huricane motor.

 

[IOPort51]

What are you using for an air cleaner on your 2 barell??

I'm a ca. guy and I just installed a motorcraft 2100 2 brrl in place of the 1brrl carter. It runs and has increased the drivability so much better. It is also supposed to pass emissions even better than the 1 brrl carter. Fuel injection would be the way to go though if your willing to spend the dinero.

 

[Sasquach]

IO do you ask that cuse the stock housing will no longer fit? I see in 777 gallery pic of his motor compartment it looks stock but maybe pre 2 barrel.
I also see a green engine.

 

[IOPort51]

It will defiantly not fit the MC with out some pretty serious hammering. I changed the one bbl manifold to a stock 2 bbl and a Carter 2 bbl (stock) the air cleaner fit but restricted the air so much it ran incredibly rich. I put a taller air filter in the hat box so there was a gap all around the sides and it works, fortunately inspection people are not always the sharpest tools in the shed, they have never noticed. But you will need to have a thermostatic air cleaner (TAC) to pass an emissions test, I think.

 

[Cheepjeep85]

you can make the factory air cleaner work for sure but like IO said it takes some hammering and enlarging the hole i had mine on my mc2100 before i bought an edelbrock air cleaner

 

[CJ777]

I kept my single port manifold and installed an adapter plate spaecifically made for the two brrl conversion. Apparrntly the single prt vs. the dual port manifolds are vertually the same as far as port size. Eventually i may install a dual port manifold just to be at spec., but for now it seems to work well with the application.

The air cleaner i went with is just a n 8" round by 2.5" tall K&N. If i'm required to have the stock air cleaner on for inspection it should be too much of a modification to make it work.
I'll take some pictures of it when i get a chance for viewing purposes. There are alot of writups here for you to check out also on the M2100 carb retrofit.

 

[81laredo]

Try these guys;
J & J Carburetors & Components Inc.
They completely rebuild the Carb including re-bushing the Throttle Assembly. Junior at J&J stated that it would pass smog when he was done. I have decided to put my $$$ into Fuel Injection instead of the miles of Vacuum Lines, etc.
I was refereed to them by a few shops on a previous project. The work they did for me was 100% so I can let you know that it was a good experience.

 

[Sasquach]

I got my smog test today and passed and am a little releived with that. Still unsure what to do though as there are so many varied options from dif. carbs to fuel injection to dif. heads to dif. engines. The one thing I would like to do is get it right the first time.
IO had posted on another thread that the AMC 258 i6 / 4.2l w/1 barrel has a dif. cam and I can confirm that after looking at the service spec. manual, lobe lift 0.AMC 232 i6 vs. 0.248 inches. And with a cam change a fairly major project especially since I had the head off and rebuilt allready and not excited about doing that again plus more. Still waiting on the TFI ignition parts and maybe that will satisfy for now. Not unhappy with the power but the hesitation and hickups are no fun.

 

[fitzp20102]

I have a related question to all of this. I'm used to my '83 with AMC 258 i6 / 4.2l . Just got a '78 with all original parts, I think... There's a vacuum line that is a hard line from the manifold to the side of the carb, but on the manifold side there's no compression fitting and o. The carb, the compression fitting isn't tight at all. Is this really a vacuum line? If so, fixing it's connections should help smooth out the performance right?

 

[Sasquach]

I have a related question to all of this. I'm used to my '83 with AMC 258 i6 / 4.2l . Just got a '78 with all original parts, I think... There's a vacuum line that is a hard line from the manifold to the side of the carb, but on the manifold side there's no compression fitting and o. The carb, the compression fitting isn't tight at all. Is this really a vacuum line? If so, fixing it's connections should help smooth out the performance right?

Thats the choke heater tube if it's coming out of the exhaust manifold and is not a vacumn line.