Soft or Hard?

[T2vigil]

Now that I have your attention. I have a modified 250. Flat top pistons, decked block .025 and a Comp Cam. It is ported to match the gaskets. The HEI I have is bone stock from the junk yard. I have been told I need a Soft Vacuum Advance. How does one tell it they have a Soft or Hard advance? Or is the best way to go is an adjustable advance?

Thanks for any info.

[64fleetside]

I always use a mid-70s big block chevy vacuum advance can-it limits the advance-it has less travel. It's a pretty obvious difference once you have the two side by side. Not sure if they fit the six HEI but I think they might be the same.

[Rich 5150 69]

Use a G.M. HEI with a soft spring vacuum advance can PN (1973691)

[T2vigil]

Thank you Rich. The local O'Rileys had one in stock and there is a large difference in the way they react. Now for one more question. The distributer has about a .25 inches of vertical play. PO installed so I have no history. What is the end play supposed to be and Where can one get the required shims? OK that is two questions.

[Rich 5150 69]

Originally Posted by T2vigil

Thank you Rich. The local O'Rileys had one in stock and there is a large difference in the way they react. Now for one more question. The distributer has about a .25 inches of vertical play. PO installed so I have no history. What is the end play supposed to be and Where can one get the required shims? OK that is two questions.

The end play should be 0.010 ..that will only allow a one degree variation. any tighter will result in excessive wear. Most speed shops will carry them or summit / Jegs

[T2vigil]

Rich, Thanks for the link. I am headed to the pick - n- Pull this afternoon to see about another HEI distributer and take the best parts to make one good one. Again thanks for the for the help.

[tincan1966]

Having the distributor blueprinted and the proper centrifical(sp?) advance setup is equally important.