I have a 66 427/425, I got it with an Mallory dist non tach drive and wanted to go back to a GM tach drive unit. I have a small block tach drive point style Dist on my shelf and have seen pictures of the Big block style.

I see the difference between the bottom of the shaft where the grove is on the big block and small block style and have heard this is for the oil path on the big block. What will i need to do to use a small block style Dist? I do not know if the engine has had the rear came bearing replaced? Can anyone point me to a good reference site or help me with a clear explination??

Thank you muchly

 

It's my understanding that you can use a sb dis. in a bb with no modifications or problems but you can't use a bb in a sb because it doesn't allow full oil flow.
If you are going original I think your 425 hp requires a TI distributor.

 

Huh? I ran my BB dist (TI) in a SB for 17 years with no ill effect.

 

Any BB or SB distributor will work. Either points or TI. With points you'll simply have to use a Ballast Resistor. You may have to do some recurving of the distributor also to get the full benefit of it for the 425.

Steve

 

They are interchangable! (not NCRS numbers matching correct, but interchangable)

 

Ralph here are 3 comments & #1 my 66 had a mallory w/ tach drive when I bought (1994 ) her (hidden under shrowd ) ...replaced in 1996 with MSD 6200 & pro billet distributer w /mech tach drive w / vac advance ........ reason starting when cold & ( not driven for a week or two ) would crank to long & idle lumpy , for first 5 minutes & gradually smooth out............ the MSD works , start instanatly idles smooth from the start & runs great right off, this MSD has not been touched since 1996.just works ..this is just my 2 cents & what works for me & my 66 BB , #2 l also installed a Optima red top battery guess 5 years ago...disconnect for winter has never been on a charger & when its hitched up my BB starts after a winter hibernation ... #3 the oiling on a vintage 1965 396 & 1966 427...are unique there is a grove in the rear of the cam & the rear cam berring has a corresponding grove to match ..the oil travels throug the grove..... this was changed & by Chevrolet in 1967 ..................the distributers for 1966 & 1967 BB , are the same as 67 on ............... just 2 cents from the Dog >>
going back into my cave ............. Woof

 

I really appreciate everyone’s reply to my question, I guess after hearing all of the information you guy's have given me, It sounds like I can put anything in there and I will not have oiling problems!

Going into the future if I tear down this engine, should I be **** about replacing the rear cam bearing and cam with a 1966 specific design or just bring it up to the newer style??


Also I will be doing a frame of at some time in the future and am trying to keep a focus on the correct configuration when replacing parts, but I can put braces on my daughter for as much as some people are asking for the original distributors!! I know that's the price you have to pay!! well I still have not gotten over that yet!

So With that said are there any other differences between the housing of the Small block tach drive and the big block other than the half grove on the bottom, I know my car had a TI, it still has the amplifier mounted on it. I was considering rebuilding the Small block dist with some new tec triggering components. I like the idea of using the MSD box Like Stray Dog has going on and want to keep the old amp in place for the visual effect!

Thanks again for all of your answers I really do aprreciate it. I was purly a chevy guy in my younger years and have been playing with porsches for a while but my brother kept calling me a trader so now I am finishing up a frame off on a 1969 396 SS ElCamino and had just picked up this Corvette last year for my next project. This site is a benifit for ignorant people like myself to become a little more dangerious and you guys are helping me get there.

 

Your block dictates the design of the rear journal of the cam and the design of the rear cam bearing. Your cam MUST have the groove in the rear journal, and you MUST use the correct '65-'66 3-hole rear cam bearing with the groove on the I.D. of the bearing, or you won't get any oil to the lifter galleries. See my "Tech Bench" column in the latest (May) issue of "Corvette Enthusiast" magazine for a complete explanation of this design, with photos.

GM tach-drive distributors are 100% interchangeable between SB's and BB's - has nothing to do with the rear cam journal/bearing issue.

 

Ralph , I replaced the cam in my 66 with a comp cam extreme energy ,I orderd my cam directly Com Cams & if memery serves me right they charged 20 bucks to do so.............that way did not have to go to a machine shop, also if you change cams its not neserry to change cam berings , as your rear baering will already have the corresponding grove in it, when you pull out old cam you will see grove >>.also its another wat to know your big block is a true vintage 65 / 66,

with Johnz , he always has the correct answer on the unusual & difficult Corvette questions , the Dog

 

STAN
Pick up the phone.
KEN