Carbed L28 problems...

[The Wingnut]

I have an early production 260 - #1024 - that, as I found out today, has been given an L28 with the stock L26 smogger carb(flattop) setup. Someone was evidently cheating...it appears to be a complete drivetrain swap, it has a 5-speed as well.

Setup is as follows: L28 block, N42 head, N36 manifolds and flattops with all of the plumbing and hoses, right down to the smog pump. No points - ignition is electronic, with a '70s Chrysler ECU(what we of the Mopar kind call an 'orange box') and matching quad-terminal ballast resistor. Ran decently until recently, when it began to sputter at freeway speeds.

The problem: Great around town. Idles well, starts easily, no oil in the water, no water in the oil. Even revs pretty decently. Get it on the road, putter around the city, behaves itself most of the time. Driving agressively, taking it up long grades, or putting it under heavy G loads seems to make the back cylinders cut out. It's not completely immediate, and it's intermittent. You can distincly hear the cylinders cut out. The car will continue on until it's starved from running on one carb...it will continue with the throttle held to the floor.

I can get about 55-60 mph out of it before it cuts out. Accelerating in any manner other than that of a grandmother will cause it to cut out. Backing off for a bit and coasting will solve the problem temporarily. I was even able to get scratch out of it the other day and tear off to wind it up through 3rd halfway before it decided not to cooperate.

I have a set of round-top 3-screw SUs from a '73, complete with linkage, heat sheild and E66 manifolds. If it's not an ignition problem, which my mechanic thinks it might be, I'd like to rip off the smog equipment and put these on, using the linkage that came with them and the N36 manifolds that are already on the car. I know there will be plenty of roadblocks, and this will not be a one-day or even a weekend job.

Also, I'd like to put feelers out for help in the Santa Rosa, CA area. I'm in Guerneville myself.

Thanks in advance!

- A.J.

[panchovisa]

Though the flat tops are not very popular try to correct the problem before switching to round tops.

Sounds like fuel starvation. New fuel filter, check fuel lines for crud. Check fuel pump for flow ( pull line, add extra hose length, pump fuel into gas can).

I've never had flat tops so someone else can help with adjusting those.

[JZM]

So what it sounds like is you have a fuel problem.you said back carb as if

you know thats were it's coming from.start there.also sounds like heat soaking

.this does not [sound]like an ignition problem.ck fuel to carbs as panchovisa mentioned.fuel filter,fuel lines,etc. also if you have a set of early carbs,put them on.you won't regret it.be sure to check your fuel filter for any tank goo

as in rust,corrosion,etc.don't forget to check fuel pressure.I hope you have some sort of service manual to also aid you in your quest. good luck!

JZM

[beandip]

You might look at the tec section and serch for SUs and adjusting SUs . Good info there . I still think the three screws you will find to be a good change. Ask around about the SM needles also. Gary