The Stovebolt Site Forums The Parking Lot Big Bolts 1969 C50, HEI distributor upgrade.

So I have a 1969 C50 with what I believe is a 350? (according to Glovebox sticker)

Was running poorly, backfiring through carb and not taking the throttle well.

Saw that it needed ignition work, decided to upgrade to HEI.

Called the parts house, they gave me a MSD Streetfire HEI distributor, said it will work no problem.

Wrong.....

Of course the oil pump drive is different.

Ok, bought new oil pump and drive shaft, removed pan, pump and drive shaft. Figured I'd install the new distributor by lining up the rotor with the mark I made on the firewall and then install oil pump and shaft from the bottom and not have to fight lining up the oil pump drive tangs.

But I can't get the distributor to fully seat? It's sitting up about 1/8" from the manifold?

What am I doing wrong and does anybody know if this combination will work?

I could use some help.

Thanks!

I'm not familiar with the MSD dists. but the factory HEI should fit. I have put them in various small block engines of different years & they always fit as long as there is firewall clearance. I understand the same dist fits big block also. If the tangs are in the slots it should bottom out. If not something is wrong with the dist.

I just looked at Rock Auto's website and it looks like all small block chevrolet engines use the same oil pump drive, Sealed Power #2246146. The Big Block engines use a different shaft and if its a big truck Big Block (Tall Deck) They use a different shaft also. What part number did you get from the parts store? Maybe they gave you a drive for a big block?

There are no tangs, the oil pump drive shaft is entirely different.

The Oil pump drive coupler on the bottom of the original distributor is a rectangular deal where as the HEI has the "flat scre drive blade" type thing to engage the tangs of the typical small block oil pump drive shaft. Is there a way to attach pics?

I can check the part number on the shaft they gave me to match up with my HEI distributor.

But that is not the issue at present because currently the oil pump and drive shaft is removed.

Wish I could figure out how to post a pic?

You can't post pics on the forum, but you can post a link to pics you put up on Photobucket or any of the numerous other places that allow picture uploads (Dropbox, Google, etc.)

Ok I will try photobucket.

Never done this before, so thanks for your patience.


<a href="http://s292.photobucket.com/user/p_learn_2008/media/NewImage2.jpg.html" target="_blank"><img src="http://i292.photobucket.com/albums/mm4/p_learn_2008/NewImage2.jpg" border="0" alt=" photo NewImage2.jpg"/></a>


and

<a href="http://s292.photobucket.com/user/p_learn_2008/media/NewImage1.jpg.html" target="_blank"><img src="http://i292.photobucket.com/albums/mm4/p_learn_2008/NewImage1.jpg" border="0" alt=" photo NewImage1.jpg"/></a>

Lets see if it works.

Those are the two distributor gears, original with the rectangular slot to fit the rectangular drive shaft that came out with the old pump and the "flat screwdriver" style of the HEI

It looks to me like the distributor shaft is broken on the old distributor.

Nope, the oil pump drive shaft is rectangular and fits into that coupler.

It's entirely different then the 2 tang style as normally seen in small block Chevy's.

Tool;

Are you sure you are dealing with a 350 or small block? Some early 366/427 tall decks had the square pump drive for the distributor. If you have changed the pump and drive, did you change to a slotted drive? If so, just take a screwdriver and turn the pump drive to line up with the distributor when you drop it in. Do you have a pic of the engine? That will clear up a lot of questions. Also the 366/427 tall decks have a longer distributor shaft to make up the difference in the deck dimensions. Good luck.

SimS

According to the sticker in the glovebox it's a 350,

What is the best way to correctly identify the engine?

How many bolts hold the valve cover on? 4 or 7 ?

There are 4 bolts holding the valve covers on.

They are blue stamped steel covers.

So I got the old brute back together.

Hit the key and it instantly fired up and idled real nice at 0f!

Soon as I drove it though it won't take the throttle and backfires like crazy through the carb just as it did before I started this adventure. What now???

Could be too much timing advance I guess but I doubt it.

Thanks for all the help so far.

Check your wires. They may be cross firing. Easiest done in the dark. Other than that I would check the fuel system.Make sure you have proper fuel level in carb, check fuel pressure and flow.

Tool;

Double check the firing order vs. the distributor wiring to the plugs. I have crossed 5 and 7 more than once!!

SimS

Its more likely to act like that if the timing is to slow. If you are timed right & sure the wires are correct its time to pull the valve covers & make sure they are all opening & closing about the same amount. If one is not it would indicate a bad camshaft. Check for a valve sticking up higher then the rest. That could indicate a recessed seat.

This guy is showing the differences between big block distributor oil pump gear that is on the C50 350 vs the standard gear on HEI small block 350 distributors.

www.youtube.com/watch?v=01-bT2xaHVc

Really dumb idea to weld it! Why not make a couple of square drive blocks for the gear with the hole drilled in the right position? Then if the pickup coil ever fails, he can disassemble it again to swap parts! Betting his engine's life on a welded oil pump drive is also stupid squared!
Jerry

You guys do know that you're replying to a 12 year old thread, right?