1970 Lemans 350 Troubles

[1970 blues]

Hi everybody. I just picked up a 70 Lemans with a TH350 and the stock 5.7 L 350 that still wears the 2bl Rochester carb. Just pulled it in my garage for an oil change. Afterwards, wouldn't shift past first and kept stalling out. I looked around for vacuum lines that may have popped off and found like 3. I reconnected one coming out of the firewall to a round valve (RH side of engine bay) that had 2 thick lines coming off (one prob heat and a thinner one that runs to the water pump). Does anyone have a vacuum hose diagram or schematic?

 

[melsg5]

You need a copy of the factory service manual. There are no vacuum hoses going to water pumps. There is usuall one short hose coming out of firewall that is left open. The vacuum modulator on the side of the trani controls shifting. There should be a rubber hose that then connects to a metal line going up to the engine. The metal line ends and there should be another rubber hose connecting to the carburetor to a constant vacuum source. In otherwords even at idle the port on the carburetor should have a vacuum signal.

 

[1970 blues]

1970 Lemans Vacuum Lines

Ok, looks like the same larger vacuum line came off again from earlier. But, the other 2 vac lines that I just capped off are still in question. I think that the plastic T-fitting coming off the back of the carb needs to go to the dist vac advance ( that's one of the open vac lines). The other line that was open actually came from the T-fitting. I'm thinking the guy that had it before me either added a duplicate line, or had a connector between the 2 (since there was a piece of red plastic that was broken off in one of the lines). The second picture is of the round Vac booster that I think you were talking about on the right side of the engine. It has a 1/4" metal male exit on the aft side of the can. Also 2 "Insulated Heater Hose" labeled hoses. One of the hoses runs through the pass side firewall and the other runs to what I thought was the water pump. It is on the same pulley as the fan. It is below the alternator, and above the harmonic balancer.

 

[melsg5]

if the vacuum can also has wires connected to it, it's part of the transmission controlled spark advance system. Vacuum advance only was applied to the distributor when the engine was in 3rd gear, part of emissions. Many people disconnected that can and ran the vacuum line directly to the distributor. In picture 2 I see the metal line that is coming up from the vacuum modulator and should be connected to a constant vacuum source. I thought you were saying you had a vacuum hose going to pump but that is one of the 2 heater hoses. The other one should be connected to the intake manifold behind the carburetor. The vacuum activated valve in the line probably shuts off hot water flow to the heater core and is activited by the positioning of your climate controls.
Just as a side note if you are looking for parts, manuals, etc. two of the better places are www.amesperf.com and www.performanceyears.com.


Another thing you can try for vacuum diagram is autozone website. Become a member, it's free, and then look up vacuum diagrams for your car.

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[1970 blues]

Hey melsg5 thanks for al your help with this and the speedocable, I really appreciate it. Like I said, I just picked up the car last week, and I freakin love it! Just tinkering around with it right now, but heads, 4bl & manifold, billet distributor with electroni ignition, a new exhaust and headers will be following soon. I'm sure I'll have some more questions later on down the road! What do you have done to yours?

 

[melsg5]

to start with it's an original 71 455HO. The heads have been milled to raise the compression from 8.4:1 to about 9:1. The exhaust system has been increased from 2.25 to a PYPES 2.5 with Dynomax VT mufflers. The distributor has been recurved and the carb was rejetted. Run a 160 degree thermostat. Has Koni shocks, larger front and rear sway bars, and went to 245/60 15 in rear with 235/60 15 tires in front. Rear gears were changed from 3.08 to 3.55 and the TH400 trani has a shift kit.
Many years ago I had installed a complete Ram Air IV package including cam, push rods, rockers, springs, and valves. Found out with a stock torque convertor it just wasnt a pleasant street car and removed everything after a couple of years and went back to the original Ram Air III cam and components.