i have a 91 camaro and i am putting in a 69 block. my flywheel doesn't match up to the crank i guess because my flywheel is for a one piece seal while my engine is now a two piece. so will a 85 camaro flywheel work. also i guess with the 85 flywheel id need a new starter too. also is the clutch the same.

 

Yes.

Nope.

Yes; buy one for a 91.

 

are u sure about the starter. my starter has straight bolt holes, while the older style has one in front of the other. although my block has dual bolt pattern for both starters.

 

Gm starter bolt patern is the same. it hasn't changed there is 2 bolts

 

That is extremely wrong. Actually, it has changed.

The early blocks have 2 bolt holes somewhat closer together than the later blocks. The outer one is in the same place on all of them, but the inner is closer to the crank on late blocks than the early ones.

The reason is that the early blocks all used 14" flywheels and flex plates. The later blocks however use 12¾" ones. The starter motor shaft has to be half of the difference, or 5/8", closer to the crank. A bolt in the early hole would have to go RIGHT THROUGH THE MIDDLE of the starter drive if it's in the inward position required by the 12¾" flywheel. It is therefore impossible for a starter to exist that will use that early-model bolt hole and also work with the 12¾" setup.

The solution is simple; have a machine shop drill & tap the extra hole. Its location is critical, and it's also a special hole, not a regular bolt hole. The outer ¼" or so is larger than the threaded part, and the starter bolts (special bolts, not just yerbasic bolts) have a special shoulder area right behind the threads that acts as a dowel pin to hold the starter exactly in its place. Without that, the starter will move away from the crank, and you'll have major problems getting it to work.

So get this done BEFORE you put the motor in the car. Believe me, it's a whole lot easier to do it then, than laying on your back in your garage under an otherwise completely installed motor that you have no way to put a starter on.

 

If you use an aftermarket mini starter, it'll have two sets of holes for the two flywheel diameters.
I've used mini starters for years though, and they tend to have problems of their own. Alignment and tooth clearance is more critical. Mine is currently shimmed a bunch on the outside and not at all on the inside (that's what I had to do to get it to quit eating flywheel ring gears and starter gears.
Like jmd said, use an older 153 tooth flywheel with a newer style clutch.
Then see if your existing starter will line up.
If not, a mini starter or a different offset factory type starter will work.
-Rich-

 

Wrong.

Doesn't matter how small the starter is or how many bolt patterns it has; if you try to use the outer one of the 2 possible inner bolt hole locations in conjunction with a starter for 12¾" ring gear, the inner bolt will still have to go RIGHT THROUGH THE MIDDLE of the starter drive. It is not possible for a block without the correct (late-model) inner hole to accept a starter for 12¾" ring gear.

Anyone who wishes not to believe, is free to try it. This subject comes up from time to time, and every single time, without exception, people find out the truth. And that truth is, if the block doesn't already have the correct hole in it which most do not, then it will have to be installed; otherwise, no starter in the world can possibly work.

However, the other part is correct; use a 83-85 T-5 flywheel. That's exactly what I have on my 400, is a stock L69 flywheel, "unbalanced" to the stock 400 balance spec. And yes, I had to drill the extra hole in my 400 block. It was one of the ones without that hole. And, yes, I have a dual-bolt-pattern mini-starter on mine too; and it still requires the correct bolt hole in the block.

 

I'm curious...what year did they make the switch and start drilling the extra hole in the block? I'm asking because right now I have a 4 bolt main 350 block out of a '78 (I believe) truck in my TA and I'm running a T-56 flywheel (out of an LT-1, 12.75" diameter, redrilled to bolt up to a 2 piece rear main crank) with a mini starter and everything bolted up and worked great, I didn't even need to shim the starter. I don't remember what bolt patterns were on my block, but I'm just curious whether there was an exact year GM started drillng the extra starter bolt pattern or if it just kinda started happening randomly in the earlier years?

-Paul

 

This is the first I've ever heard of a different in-block starter bolt pattern. I was under the impression that early (like 55 Chevy) small blocks had the starter bolted to the bellhousing. And there are of course the straight pattern (with unequal length bolts) for a 153 flywheel. And there is the offset pattern (with equal length bolts) for the 168 flywheels.

What have I missed (which happened before I was born, but anyways...) here? Since 153 wheels go back to the 60's, I'm lost on what you mean by "late blocks."


edit: I think I got your meaning now.

You're saying that some '70's and older(?) blocks weren't drilled for the 153 pattern. Makes sense for 400's since they weren't produced with 153 wheels whatsoever to the best of my knowledge. But the 153 wheels go back previous to 400 blocks, so I guess you're just saying that 100% of production being dual-drilled blocks are a thing of the 80's and beyond.

 

all the blocks i've had have had this pattern...It sound like you are saying hole #2 is further from the pan rail on some blocks. All i've ever used it hole# 1 and #2, whether it was with a 14" or 12 3/4" flywheel. I think some early block didn't have the #2 hole, and used the #3 hole, that's all i've ever seen. And i've seen a few, like my current 400 block (forgot the casting #) and my 0010 casting block, and my late model block. they were all the same though.

 

like this...


Why won't it show the pic...

 

well thanks for the replies, engine is in with a 85 flywheel and my stock 91 starter, all on a 69 block