Distributor difference - small vs. big block

[Everett Ogilvie]

The groove in the distributor body just above the drive gear is different for midyear small and big block distributors - the small block groove is 360 degrees and the big block groove is about 270 degrees. I have heard this groove difference is to control oil flow in the big block. I have also heard you can use one style in either engine, but both styles are not interchangable. Is it safe to use the small block distributor in a big block? Are there any consequences such as reduced, or increased oiling to the top end?

[John M.]

Re: Distributor difference - small vs. big block

Everett, I've been using a small block distributor in my 69 L71 BB for about 3 years now without any problems. I've adjusted valve lash and had oil everywhere if that's any indicator of oil flow. It does have a high pressure pump. The TI setup has let me down too often.

[Wayne M.]

Re: Distributor difference - small vs. big block

Everett --- I think the groove applies only to '65 and '66 BB's, and this mod was in conjunction with the "stock" size of the oiling hole in the rear cam bearing and the grooved rear cam journal. On the big block side of the story, I've heard arguments that changing certain combinations can cause either a massive upper oil leak, or starvation. There are earlier discussions on this board, but not much concerning the effect of the BB distributor. I am curious to what will be said about a '65-'66 SB distr. in a big block. And I would add: what about the reverse situation ?

[Clem Z.]

Re: Distributor difference - small vs. big block

as long as the solid part of the "groove" is not blocking the oil gallery hole there is no problem. if you do not feel safe doing this just have the the groove machined all the way around the housing.

[Everett Ogilvie]

Re: Distributor difference - small vs. big block

Clem, are you talking about using a big block distributor in a small block? What about the big block distributor in a big block - could you rotate the distributor enough so that the solid area blocked oil flow? If so, why is the solid part there in the first place? Is it unique to the '66 setup? Did original '67 big block distributors have a full or a partial groove?

[Clem Z.]

Re: Distributor difference - small vs. big block

in 1965/66 we ran a SBC vertex magneto in a BBC with no problems and it had the complete groove in the post. i was not aware of the partial groove posts till much later and i never did find out why that was done. with the vacuum can on the distributor i do not think you could turn the distrbutor to block the hole in the block

[Joe L.]

Re: Distributor difference - small vs. big block

Everett-----

I THINK that the "interrupted oil groove" distributors were used on all 65-67 big blocks. There was no reason, at all, that they were necessary for 1967, but I think that they still used them. As clem says, I don't think that they were necessary for 65-66 big blocks, either. The fact that clem ran full groove distributors on 65-66 big blocks "proves my theory".

Why these were used on early big blocks, I have no idea.