MDchanic

Those pistons and bearings look great.

Since it's already apart, give it a quick hone, new rings and bearings, and put it back together.
If you're ambitious, have the heads decked about 0.030-0.040" to make up for the change in head gasket thickness and increase the compression slightly.

The head sealing surface adjacent to each cylinder will be stamped with letters corresponding to the piston crown stamps - you've got to really look for them.

- Eric

olds 307 and 403

To hit your 9 to 1 goal, contact Smitty at M&J Proformance. He can get .011" thick shim heads gaskets. They aren't cheap but neither is machine work. No wonder Olds V8's lasted like they did with the matching of pistons to bores and other quality work.

cdrod

Thanks Joe!

cdrod

I've cleaned the sealing surface of the block under the head gasket and found the stamped letters to match up with the pistons stampings. The odd cylinder bank is all "B" sized pistons and the even bank has a "B", a "D", and 2 "C"s. I have a few more questions:
1. Shouldn't all the rod caps face up? By this I mean the bearing notches should face up towards the cam. I have some that face up and some facing down.
2. This question is for 70vert, It seems like all of my rods are chamfered on both sides (not just one side). Some rods have a little more chamfering on one side vs. the other, but most are the same on both sides.
3. One rod and cap looks chewed up (see the picture). Is this just on the surface or is this a bad rod? I was told the engine was running before I bought it, but I never ran it myself so I'm questioning everything.

Block Diagram


Matching everything up


Block stamping


Is this rod OK or should it be replaced?

coppercutlass

The bearings have an off set atleast the rods off the 355 im working on now are. set a bearing half in the rod and look at the sides one side will have more of the rod bore exposed than one that side goes towards the counter wheight. I once had a shop swap two rods and they installed them wrong so the bearing tangs faced the pan rail vs the cam and it seized the engine up as soon as i torqued the rod caps. Although on newer engines i think after mid 70's the rods had no front or back as they didnt have a spit hole . Its a confusing subject and i got confused on my current build as 3 rods where replaced when it was built by its previous owner and they didnt have the spit hole so i went by valve relief placement and location of the bearing tangs. I actually talked to 80rocket about this earlier today becasue there is some mixed up info on the correct way to install the rods. i have never built a 350 older than 76 so i cant say you can or cannot install the rods backwards or forward with out issue but on my last frankenstine junker build where 3 rods where installed backwards i had issues during assembly. I would look at the position of the pistons and offset of the bearing to determine piston location.

cdrod

Sorry guys, I don't know what happened but I've fixed the missing pics in Post#46.

cdrod

Copper:
I'm referencing a '71 CSM (which shows the "spit" hole in the rod cap) but the block is a '76 so maybe the this motor doesn't have the spit holes and the orientation of the rods and caps doesn't matter. This would have been much easier if it wasn't suck an F-ing puzzle!

I ran a dial bore gauge down all the cylinders and most have a taper of .002-.003". What's interesting to me (and I have little experience with engine building) is the taper variation is worse when measured side-side (front-to-back). When I measure top to bottom (where the piston skirt rides) there is much less variation ~ .001" at the most. Is this normal?

cdrod

None of the bearings have spun - they all have the indexing tabs intact. I think I can get away with polishing the crank and not have to turn it down .010" I haven't checked cam bearings yet. I was planning on a roller cam for the stroker build, maybe overkill for this down-and-dirty rebuild. Does a roller cam need a special bearing size? I think they need a torrington thrust bearing at the front of the block.

70vert

What copper said. The bearing should be offset in the rod by a little bit. The side that the bearing is farther from the edge faces the crank. You have one piston that you know for sure where it was so use process of elimination to see which way the bearing tangs face. Then you can arrange your Pistons with the v notch facing the front of the block and the bearing notches all facing the same direction.

70vert

That one rod looks like somebody had a bad day in the rod machining shop Lol. It will be fine.

cdrod

I want to say thanks to everyone who offered up support and advice concerning my engine overhaul. After a little reflection I've decided not to simply re-ring this motor and to move forward with my SBO stroker plans. Truth is, I hate to do things twice. The more I thought about doing a quick rebuild of this engine and then pulling it later on to do the stroker build the more pissed off I got with the local engine builder. So I looked up a machinist I had used 20+ years ago, who is semi-retired but still has his shop. He & I came to an agreement on the machining costs, I will provide all the parts and he's going to let me help with the blueprinting and then let me assemble the engine myself. Not only is his price clear and firm, but I can do some of the work to save on labor costs. I've crunched the numbers pretty hard and have a clear budget for this build now - which is what I wanted from the previous engine builder. I will post my budget in my other thread for those that want to see what this will cost, and those that can advise me of any errors I may have made.