So, I'm changing to a Weber DVG carb on my 67's b18 engine. What exhaust manifold should I be using with it?

Either cut the intake portion off the stock manifold, or hunt for a manifold from a fuel-injected B20.

His '67 B18 should already have a separate exhaust manifold... so the stock one can be used. Or, find a dual downpipe from the FI B20 for a little more power.

One thing to keep in mind... sometimes the thickness of the weber manifold is different wehre the thick warshers go... you have to either grind warshers to suit, or grind manifolds to same thickness. Them warshers have to sit flat or you'll probably have vacuum leaks...

And... don't expect a great power gain with the new carb. But once you get it set up right, you'll like the smoothness and the fact you won't have to tinker as often.... But keep your old SUs around in case you decide to switch back someday!

Good luck!
-Matt

A '67 1800 would have the unified intake/exhaust manifold. That's the bad news. The good news is that it would have the dual downpipes and be the correct thickness to match with the Cannon intake. 122s might still have had the separate, single downpipe rig in early '67, not sure -- typically, 1800s got improvements first, then 122s with a trunk, and wagons last.

OK... I'll trust you :-) Only experience I've ever had with '67s has been with 122s...which all have separate manifolds even through '68 I think. I had always thought that the unified manifold came along with the introduction of the B20 in '69...

-Matt

I had a Weber on my B20 144 and switched back to SU's. The weber is easy to adjust and jet, and it also sounds cool when the secondaries kick in. Idle is very smooth. The problem with the weber, I found, was that it doesn't run as well in the cold (below 50 degrees), the choke isn't as effective as the later SU's and the small open air cleaner on the weber gives the motor a loud sucking sound on acceleration. I also had a problem with engine case pressure because the vacuum inputs on the manifold are different than the factory ones on the SU manifold. This lead to oil leak problems on my car (which is the main reason I went back to the SU's). It's possible there were other contributing factors, since I bought the car with the weber already on it. There are pros and cons to each.

Mine had icing problems on cold days too. It's essential to hook up the water lines to the manifold, which helps at least somewhat.

There should be no problems with crankcase pressure if you hook it up "B18 fashion," with the teardrop connected to the manifold through a PCV valve, and the oil filler cap hooked to the air filter.

Downstream, that's the combo I contemplate for my 73 1800ES. I'm only considering the single Weber 45 DCOE rather than a pair of them. Does anyone have experience with that particular modification, and can I expect any power change from the D-Jet to a carburated configuration - decrease or increase?

Joe K

I've used the Lynx crossover manifold with a single 45. It's interesting, but not exciting, good torque around 2000rpm, but then it only really equals a pair of SU's in the midrange. I could never get it to run economically either, the SU's are very hard to beat for MPG's.