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Bored&Stroked · 12-18-2025, 08:32 AM

These are the standard large-journal full-floating rods used on Mercury engines from 1939 - 1942 and on Ford Truck/Industrial engines from the same time period.

The '99A' is associated with Mercury and truck engines between 39 - 42 (and also during the war). The other (more common) part number you can use is for later '29A' full-floater rods. These rods are usually in 1945 to 1948 engines and are readily available.

If you're going to replace one rod, you should consider replacing ALL of them as a balanced set. You should be able to find a NOS set of eBay for a decent price. Also, you should replace ALL of the rod-bearings and make sure you know how to tune/fit the bearings to the rods and crank.

These are called "full-floaters" for a reason - the bearings must float and easily turn inside the rod and on the rod journal.

Is the engine all apart? What does the crank look like?

12-18-2025, 08:32 AM	#2
Bored&Stroked Senior Member Join Date: Jan 2011 Location: Central Ohio Posts: 5,906	Re: Connecting rod identification These are the standard large-journal full-floating rods used on Mercury engines from 1939 - 1942 and on Ford Truck/Industrial engines from the same time period. The '99A' is associated with Mercury and truck engines between 39 - 42 (and also during the war). The other (more common) part number you can use is for later '29A' full-floater rods. These rods are usually in 1945 to 1948 engines and are readily available. If you're going to replace one rod, you should consider replacing ALL of them as a balanced set. You should be able to find a NOS set of eBay for a decent price. Also, you should replace ALL of the rod-bearings and make sure you know how to tune/fit the bearings to the rods and crank. These are called "full-floaters" for a reason - the bearings must float and easily turn inside the rod and on the rod journal. Is the engine all apart? What does the crank look like? Last edited by Bored&Stroked; 12-18-2025 at 08:50 AM.