Hi my names Bill and I'm a caraholic...I've been living with it ever since I could walk and it has now culminated into a torn apart engine from a Pontiac that I'm struggling to get back together. I bought the car and tuned it up and in the process got two plug wires flipped and washed out the bearings with thinned out oil due to unburnt gas. (Nice job champ) I've had the block out for dip, cam bearings, hone, and line bore along with crank checked. I have purchased the following:

Performer Intake high rise
KB dish pistons
Procomp 350 heads
SS roller rockers
Cam
Recon rods (nothing available aftermarket)
Summit MAX-efi500

I'm pretty much at step two - I{'ve got the crank sorted out and ready to put the pistons in but am confused on the orientation. The machine shop installed the pistons on the rods all the same way and with aligning the pistons correctly puts 4 rods with tangs to the pan and 4 rods with tangs to the crank? Is this possible - I know its not normal and understand the important part is getting the chamfer against the crank cheek ( he said cheek) ((I'm almost 53 and live a sad life)). Heres the thing though - of the few videos exist of teardowns of a 403 have all the tabs (not tangs) pointing to the rear of the engine?? All this to say is there a person here that has experience orienting the rods of a 403? If so I would very much like to have a conversation. Heck if you know for certain with out a doubt I'll even pay you for the knowledge you posses that I lack.

 

Oldsmobile rods do not have an offset so it really does not matter which way they go. The older rods used to have an oil squirt hole that pointed to the camshaft but they did away with it somewhere along the line.

I always put them on in two directions and number them but a lot of shops do not. Here is the text from one of my AERA bulletins:


PISTON TO ROD ORIENTATION ON OLDS V8

Piston To Rod Orientation On Oldsmobile V-8 Engines AERA members have reported confusion over piston to rod orientation on Oldsmobile V-8 engines. The confusion centers around the fact that not all Oldsmobile V-8 connecting rods have squirt holes at the parting lines.

It has also been reported that engines using the later type connecting rod without the squirt hole have random piston to rod orientation. When using connecting rods with a squirt hole, assemble the piston to the rod with the squirt hole facing the center (inboard) of the engine. When using connecting rods without squirt holes, there is no specified piston to rod orientation.

Because these rods have neither a squirt hole or front and rear side, they can be assembled to the pistons at random. For purposes of uniformity, it is recommended that a specific procedure be adopted for assembling this type of rod to the pistons. A good choice would be with bearing tangs to the outside of the engine, which is common with other GM engines.

The AERA Technical Committee

 

Wow - thank you so much! I also tried a different search topic focusing on bottom end and not just a build and came across several vids of oil pan off. The caps have a tab on the chamfered side that is not always the same in every engine (assuming it was never taken apart before and was looking at factory assembly. I'm gonna put it together without rings and rotate - if its all good I'm gonna let tit fly.

Thanks again!

 

Molnar and Scat both make a rod for the Olds 330-350-403.
Cam specs? The std KB pistons won’t give you a comp boost. In fact I believe they’re shorter than stock, which will reduce your comp.
Just an fyi.

 

roger that - yeah its the heads making more pressure.

 

If you’re relying on Junior at Olds Rocket parts to correctly measure the chamber on those heads, you may be in for a surprise. I’d have them checked before you install them. Just sayin.