Dual Point Distributor without vacuum advance in 68 GT350

[Britton]

I know the 68 GT350s used a C8ZE distributor with vacuum advance but was wondering if a C5OF dual point distributor could be made to work with an automatic 68 350?

[shelbydoug]

Yes but the vacuum advance will give you about two more miles per gallon.

A better compromise would be to run a Boss 302 dual point distributor with a vacuum advance but all of them will work fine.

[427hunter]

The reason automatic cars have vacuum advance is for efficiency during general diving conditions. At a particular rpm/speed you may have 50 degrees of advance to have more burn time and be a little leaner rather than richer and more responsive. The mechanical only distributor will work but not as described above, it will have most likely 12 initial and 34 total and be less efficient for your car in street driving conditions.

[shelbydoug]

The reason automatic cars have vacuum advance is for efficiency during general diving conditions. At a particular rpm/speed you may have 50 degrees of advance to have more burn time and be a little leaner rather than richer and more responsive. The mechanical only distributor will work but not as described above, it will have most likely 12 initial and 34 total and be less efficient for your car in street driving conditions.

Yes. That is the intent of the vacuum advance.

The issue with it in high rpm use is that the point plate tends to vibrate and cause timing inaccuracy.

Even the "Off Highway Boss 302" booklet recommended removing the vacuum advance, pinning the point plate and plugging the hole for racing purposes.

"Somewhere" it was mentioned that 6,000 rpm was about the limit with a vacuum advance distributor (of the era) before it would start to bounce the points.

[s2ms]

Hi Britton,

It will work well.  Years ago I had a 65 FB auto with a warmed over 289 that I put a C5OF HiPo distributor in, ran great.

Dave

[JohnSlack]

Yes but the vacuum advance will give you about two more miles per gallon.

A better compromise would be to run a Boss 302 dual point distributor with a vacuum advance but all of them will work fine.

Doug,
Not trying to be offensive but that's a $3,000.00 answer to a couple of hundred dollar question. Just use the C5OE hipo distributor and enjoy the car. Even though gasoline prices are really high right now it will still take you a long time to recoup the cost of a BOSS 302 dual point distributor.

John

[shelbydoug]

Yes but the vacuum advance will give you about two more miles per gallon.

A better compromise would be to run a Boss 302 dual point distributor with a vacuum advance but all of them will work fine.

Doug,
Not trying to be offensive but that's a $3,000.00 answer to a couple of hundred dollar question. Just use the C5OE hipo distributor and enjoy the car. Even though gasoline prices are really high right now it will still take you a long time to recoup the cost of a BOSS 302 dual point distributor.

John

Cost was never mentioned but you can build one for about the cost of a 289 dual point used at around $500. It doesn't need to be original does it?

Perogie has the cam and the points plate. You can use a Standard vacuum can. Put it together in whatever existing housing you have now.

The vacuum advance can is adjustable with an Allen wrench through the vacuum port.

For an automatic transmission in want for a dual point distributor, this would be the best combination. a very good solution.