See attached pictures. On my 2bbl manifold I have what looks to be a steel line going into the manifold. Top left of picture. If you look at the picture of my 4bbl it doesn't have anywhere for that line to go. Anyone know why? Thanks.
Hey , 4bbl manifold looking good . That fitting in same approx location on the 4bbl intake must thread out of there correct ? Will your 2bbl line n fitting replace it ? Probably NPT threads . Does that line go to brake booster ? Been awhile since I've had a 300 to work on .
Thanks. The line on the other side (right side of your look down at the manifold) goes to the break booster. The line on the left which I am talking about runs down the back of the engine to somewhere.
There's no hole or place for that line on the left side to go on my 4bbl. Curious as to what it's for and wonder why there is no place to put it on my 4bll intake.
Looks like that line may be for the vacuum modulator on the trans if in a st300 has one of those, I can't recall. Just drill and tap the hole you need, easy peasy, down the road.
Ok . I see I think . Does that line go down to the trans modulator ? That looks like the line on my 64 but it went to a fitting under carb . Could remove lower left plug to see if same size threads . All should read manifold signal . The modulator is a can on right rear of trans . There's a diaphragm inside and if bad will affect trans operation and can leak atf up into intake . I had atf in my distributor that came from that .
Yes, it runs from the intake to the module on the ST300 tranny. This is the 300/ST300 out of my 1964 Skylark.
Thanks for the responses. Do I need to hook it up into my 4bbl intake? If so I'll try that plug first. Don't really want to drill a hole into the manifold but I guess I might have to.
Yes, if you want the tranny to shift correctly with engine load/vacuum pulled at various throttle position. That is what that modulator does. You should not need to drill any holes. You have three places you can use, I would start with the back. (if that is plenum and not water) the two up front are on runners. And you can almost always use a T-fitting. If you need brass fittings, these guys have a lot of stuff, and are "old school" warehouse with rows of old metal shelves and cardboard boxes with oodles of fittings. They make hydraulic system hoses, pneumatic and air lines, so they are a good source. From NPT, to AN, compression, etc. https://www.rubberandspecialties.com
Well, you can always tee into somewhere else that has full manifold vacuum to make it functional. But I don't think it would look as good as it hooking up where the 2bbl line went in, dealers choice though. Just make sure you blow out all the drill shavings if you go that route. GL
Thanks. The top left hole is for the break booster line. I will probably remove the plug from the bottom left hole and make it work. That's close to where the line went in on my 2bbl intake.
