Vacuum Source - 1958 Dual Quad

[Richard M.]

Re: Vacuum Source - 1958 Dual Quad

Tom,

That manifold more forward open threaded hole goes into the lifter valley, not the intake plenum area. Some manifolds were open, some closed. All I have ever seen were open though.

I've used the NAPA IC12 coil with success many times.

Rich
ps You could make your own hollow stud if you have a good drill press or a friend with a Bridgeport.

[Thomas H.]

Re: Vacuum Source - 1958 Dual Quad

Tom,

That manifold more forward open threaded hole goes into the lifter valley, not the intake plenum area. Some manifolds were open, some closed. All I have ever seen were open though.

I've used the NAPA IC12 coil with success many times.

Rich
ps You could make your own hollow stud if you have a good drill press or a friend with a Bridgeport.

Rich,

I have access to a milling machine at work. Should be first order of business on Monday............

I put a different coil on and now I'm enjoying 8 to 10kV of secondary spark vs the 5 to 6 kV that I had with the new reproduction coil. Throttle response is much better.......

I put a couple bolts in those holes anyway......... Didn't look like it went into the lifter valley as I could see aluminum on the other side. I'll try turning the garage lights off, shining a light down the carb and look to see if I can see the light through the hole.

20151119_175111.jpg20151120_173612.jpg

[Richard M.]

Re: Vacuum Source - 1958 Dual Quad

Reference CF thread about the "hole" from you know where.....

http://www.corvetteforum.com/forums/c1-and-c2-corvettes/3569693-58-oil-spitting-from-under-distributor-3.html#post1588386996

manifold backside/topside photos for reference. On the rear view you can see the hole heads into the lifter area. I don't know if some were blind or some were drilled. Jury is still out.

Dual_Four_Intake_Rear_View3739653.jpgDual_Four_Intake_Top_View3739653.jpg

[Thomas H.]

Re: Vacuum Source - 1958 Dual Quad

Reference CF thread about the "hole" from you know where.....

Rich,

Got too excited thinking I found a vacuum leak and also a source of vacuum...... Double checking, yes as you state, the hole goes into the lifter valley. The "aluminum" I saw was the reflection of my flashlight off the iron block - using a bright white LED light.

Got it running pretty well now. Hopefully I can get some time tomorrow afternoon to take it out for a spin.

As usual, thanks to you and Frank for the help.

Tom