Featured Technical My '40 Ford Pickup 'Hot rod' Project

1949 (8ba/8rt) went to the new style insert bearings.

Correct me if I'm wrong, but you can run later rods on an earlier crank without issue. Or, even swap a later crank & rods into the early block.

Hope you didn't deck that block much. That's one machining step that's recommended to skip with the flatty...

3blap.

 

The rods, bearings and the crank must match. If you use later rods and bearings on an early crank you will lose oil pressure. The single oil galley located in the center of the journal blows the oil out of the gap between the rods equipped with new style individual bearings. This is a lesson I learned the hard way.

 

My belief is they started in 32 and all 21 stud motors used them. Nothing wrong with them as long as all machine work is done correctly. Mix-n-Match has been done forever pending what you're doing. I've heard that early rods/bearings and a late Crank ground to match can give you more stroke ending with a little more compression. At 80 years young me instant recall can be incorrect. Look at your Rod big end. If you have index locks you should have 2 bearing inserts. That's late style. Late cranks will go into a 21-stud block if you know how to get there.

 

Sort of correct. The Oil Pump will make pressure no matter what or where it's sending oil to. Your gauge will tell you everything is fine. The delivery route isn't going to do its proper job.

 

It was my gauge that showed I had a problem (I had an early crank, with late rods). The oil pressure gauge displayed very low oil pressure.

 

That totally makes sense! Tough lesson to learn!

3blap.

 

I enlarged the pic under the workbench to see if the crank rod journal had 1 hole, or 2. I still couldn't tell for sure, so I asked.

 

I see two...

 

Sure enough! The next journal has 2 as well. Not to mention, the crank should have an 8ba cast into it.

3blap.

 

Flatheads used 3 different versions of the full-floaters from 1932-1948.

 

Thanks , anothercarguy. I have a 59A in my '41 p/u and it had all new bearings and they did fit they are correct for the crank and rods after some careful refitting. Big learning experience.

 

You can use the 21 rods with floating bearings on a late crank just fine. That’s the combo to use with offset grinding to stroke the Merc crank to 4-1/8”.

 

Got the rearend done (I think). Housing is mounted to the parallel leafs, brakes mounted to housing, and axles inserted into third member with drums. All I need now, are some wheels and tires. Thinking 7" wide with 215-75 R15's.

 

Maybe, but 59A main bearings fit, while 8BA bearings do not.

 

Minimal work today, but did get one of the fender liners blasted, acid etched and ready for paint.


Acid applied and etching the steel.


After pressure washing and drying the panel is ready for urethane primer and paint. I'm thinking a lighter color than stock like grayish green, or greenish gray or grayish gray to brighten up the engine bay. Engine is red. Stock was kinda Army green like the rest of the truck.

 

Black would look good, I think.

 

I powder coated mine semi-flat black, easy to wipe off and look sano. I also powder coated the front fender braces (fill panels) behind the tires. They take a bit of abuse, I didn't want paint down there. (Crown bag didn't stay).

 

I have been thinking about your firewall/ inner fender combo for my '41. Powder coat is a great idea.