How to Rebuild a Corvette 454 Engine - Part 7

While selecting my engine components I decided to go with new I-beam connecting rods. Although they are similar in shape to the stock rods, they're quite a bit stronger. I also chose rods slightly longer than the stock connecting rods (6.385" vs. 6.185"). I chose a longer rod because the new pistons I decided on were slightly shorter than the originals. In order to have the top of the new piston travel to the same height as the old piston I needed to go with a longer rod. Lastly, I decided to go with bushed wrist pins instead of press-fit, this was simply a matter of preference.

The wrist pins I purchased are held in the piston by using devices called Spiro Lox. The Spiro Lox are thin coils of steel that resemble a spring when the ends are pulled apart. They're installed into grooves in the wrist pin bore and prevent side to side movement of the wrist pin.

After installing two Spiro Lox on one side of the piston I determined the proper orientation of the connecting rod (one face of the connecting rod should be stamped, this face should be toward the outside of the block when installed). I also determined the proper piston orientation. Once I had the rods and pistons properly orientated I oiled one wrist pin and slid it into into the pin bore until it bottomed on the Spiro Lox. After getting the pin in place the remaining two Spiro Lox were put in place.

Installation of all the Spiro Lox was pretty much a pain in the butt. After a few I developed a feel for it, but with 32 of them all together my thumbs and fingers were pretty sore by the time I was done.

So, after several hours of work, below is a typical piston and rod assembly. Next step, get them installed in the block, right?

Well, hold on! Before I can install the pistons, I needed to get the crankshaft in place. With all this work new main bearings were definitely in order. I decided to go with Speed Pro (Federal Mogul) competition bearings that feature a 3/4 groove (as opposed to stock 1/2 groove) for improved oiling. I also purchased 0.001" oversize bearings since my main bearing bores had been align honed at the machine shop.

From the start I knew I planned on Plastigaging the bearings so my first assembly was simply a dry run. With that in mind I placed the top half of the bearings in the block and did not oil them. Once I finish with the Plastigage I'll remove and clean everything one more time before final assembly.

Here's the crankshaft back from the machine shop all cleaned up and ready to be installed. Originally when I took the crankshaft to the machine shop I was a bit concerned because there were several small knicks in the journals. Lucky for me the machine shop was able to polish them out and the crank came back looking great!

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