One bbl vs 2 bbl '73 258 intake

Since I need a new exhaust manifold (mine was cracked before it sold to original owner in 1974, and was welded by dealer. Weld failed, jeep has 44 k miles, sat unused in the 'glades for 30 yrs)
Is it worth the two-barrel swap? I have chance to potentially purchase a complete assembled factory manifold pair, rather than trying to Ni-rod weld the old crack. Or should I just stick to the 1 barrel, which still works fine after I disassembled and cleaned it? Also have access to a cheap header, but I am not sure that's worth it either.

My search has noted that the later two barrel intakes rotate the carb ninety degrees so they are across, the earlier ones the intakes are in line. Obviously the linkage needs to be modified, but are there other problems with the later setup?

To recap, the CJ 5 will do 99% off-road log pulling mule duty on my mountain acreage.

 

from my own experience the stock cast iron manifold on a 258 is your best bet for 9/10 peoples applications..
they are made aftermarket and if you get it jet hot coated it will look as good as the day you put it on..

the 2 bbl on a 258 makes a world of difference at higher RPMS.. not log pulling

 

My '77 J-10 came with the first year of 2V manifolds on 258s. It had a cast iron 2V intake and the same exhaust manifold as the earlier engines. It also was the first year for the Carter BBD on a 258, before the notorious computer control. These engines are quite susceptible to leaking between the manifolds and the head. When they leak, the exhaust gas erodes the machined surfaces and prevents them from sealing, even with a gasket. My manifolds were in bad shape - though they could have been saved by machining the gasket surfaces. I chose instead to use the manifolds from a 1985 CJ that I got from someone on my local Jeep forum.

The later manifolds (1981 on) are much smoother than the earlier manifolds, and the exhaust casting is lighter - which I attribute to much improved casting technology. The intake manifold is aluminum and warmed by cooling water. The heater hoses route the coolant through the manifold. There is also an electric heater in the manifold that warms the air-fuel mixture for better drivability when cold (not connected on my truck - but it could be).

These newer manifolds bolt on, though I did have to notch the power steering bracket a bit to clear the exhaust runner. I equipped my Jeep with a Motorcraft 2100 that I got at a wrecking yard. Works fine, but I'm now working on swapping over to throttle body fuel injection. The other popular choice is the Weber carburetor imported by Redline. I would avoid the factory BBD carburetor - everybody hates it.

Get the throttle linkage along with the manifolds. My linkage came from a different Jeep (A TJ?) than the manifolds, but it all goes together fine. Use the throttle cable from the donor, and the factory linkage used with the BBD pulls down. This can easily be adapted to the Motorcraft with a simple bracket, and the Weber uses the original linkage.

For me, the new manifolds were a three-fer. I got rid of the troublesome Carter BBD that came on my truck, repaired the intake and exhaust leaks at the manifold, and eliminated the rusty and leaky pre-heat flap in the original manifolds.

 

To me, tubing headers are expensive, hot, fragile, leaky, and noisy. Otherwise they are great.

Tubing headers are race-car tech. They do improve performance, but the iron manifolds have advantages too. They radiate less heat to the engine compartment, they are quiet, they are strong, they are durable (no rust-through) and they are much less prone to leak.

IMO tubing headers are a bad choice for a Jeep that goes off the street much. You are much better off with a cast iron manifold. And, the later manifolds are much smoother, so you can get some performance advantage from them.

 

Thanks Tim, that has been my experience with headers. I'm really not considering them, just that it was available with a one bbl carter intake combo.

Thanks to your suggestion will refine my search for the later manifold pair and replacement carb, perhaps a 2100. Is the smaller venturi 2150 a viable alternative? Also am assuming the electronic EEC-IV is one to avoid?