I replaced the HS6 on my '68 144 with HIF6s. Old HS6s had very worn shafts. It ran ok but was hard to keep in tune. I rebuilt and cleaned the HIF6s prior to installing them. I found a crack on my B18 combo manifold. I sourced a replacement. Put on new manifold studs and intake/exhaust gasket. I used the plastic spacer and all the gaskets for the HIF6s. I'm using the newer style one piece air filter as the elements are easy to source.

Its takes a lot of cranking to get it started. Many tries to keep it running. Need to leave the choke on to keep it going. I only have the front HIF6 carb enrichment. After a bit it will idle. I preset the jet adjustment level with the bridge and then two turns in. I can get it to idle a bit. Anything off idle it wants to stall. Nothing else was changed when the carbs were pulled and replaced with HIF6s.

I had checked the valves and compression prior. I checked points and timing. I had a suspect fuel pump. I replaced with a used Pierburg. No improvement. I pulled the plugs which are pretty new. Running very lean. Pulled carbs and checked the float settings. Fine there. No dirt.

The other day I had it running and happened to plug the PCV connection. RIght away I noticed an improvement. I have not had any time to work on it since. I started thinking about the way the B18 had the PCV and power brakes plumbed in. The PCV and power brake lines merged to one and connect to the imtake manifold. That was the only intake connection I had with the HS6. This is a large vacuum on one of the HIF6s. The other has a small connection. These are not the hot start connections.

I was wondering if the vacuum setup is my issue or at least needs addressed. I did check the valve at the power brake booster. All seems ok there. I was reviewing the B18 vs B20 PCV setup on the following page and wondered if I should move the the B20 setup. I need to see if my replacement manifold has the restricted intake nipple.

http://sw-em.com/pcv_diagrams.htm

The way the PCV and power brakes were plumbed seemed to work with the HS6s. Not sure how else it could have been setup with the one intake tap. Wondering where I can go from here to get it running right.

Craig