quaddriver

*is this the right place to ask this? I am still new here...*

anyways, IT has been my experience that Olds made good use of TVS's all over the place. This 78 49 state (8BFV calibration) 403 has none. there is none for the HEI dizzy which was the most surprising. The VECI is still inact on the cowl (currently in the trunk) and its in good shape and correct for the car.

The carb however does NOT have capped idle mix screws which leads me to believe something got swapped out....

Basically what I found was, the base gasket was broken in 4 places into 5 pieces and it leaked vacuum so bad, the PO opened the mix screws so much....

Got the carb rebuild kit from AZ (gp sorenson) and it does a lot of generalization of course, 13/32 float and 9/32 accel pump settings sound about right and it contained a new base gasket! the carb is soaking as are most of the bolt on parts and I am trying to replace/rewire the hoses, essentially the vacuum for the tranny modulator and the dizzy are shared, the same thermal in the air cleaner works the choke pull off and the autotherm (is that right? my memory is failing me....) there is no EFE valve on this car...just a lot of stuff on the 350s 74-77 that I dont see here.

any words of sage advice?

joe_padavano

Um, get a 1978 Chassis Service Manual?

For what it's worth, AutoZone has this 403 vacuum diagram that allegedly covers the 1978 cars. I wouldn't trust it, but it does appear to match your car's equipment.

quaddriver

The auto zone one is close....but the one on the car does not have the DTVS included.

sadly, I had all the olds service manuals from Terry Kisers (#44 NAscar from NoVA) shop from 65-86 and sold them all for too little at Carlisle 2 years ago...but who knew Id get this car...?

Im not afraid to not use the TVS as we have no emmissions here, and they way they have it running it always has a good load on it, the 403s suffer siamese bore heaating issues like the chevy hence cooler is better? its not earth stopping but dayam, this 78 has less emission stuff on it than my 74s did...

joe_padavano

The DTVS is there solely to switch the distributor from ported to manifold vacuum if the engine starts to heat up. If you are currently running advance only on ported vac, you want the DTVS, or else you want to switch to manifold vac only for the advance.