Technical Roothawg's 390 Cadillac build

So, after a long deliberation I decided on a powerplant for my 1936 Ford pickup. This is an important decision for me, because this will be my last powerplant for this truck. I have had the truck since my dad bought it for me in 1970.


I drove it all through high school. It's been apart 3 different times.
Here it is in 1978. My sister riding her Pixie.



So, I decided on Cadillac power. I started watching Craigslist, nothing around Oklahoma City. I finally found a 1962 390 in downtown Dallas. It was in an old single car garage, in the ghetto. Pretty sketchy neighborhood. The dude that was selling it wasn't a car guy, more like a tweaker. I picked it up for $200.

I was afraid it was junk, but I had to take a chance. The reason I went ahead and decided to buy it was, it was inside, covered up and someone had built an engine dolly. If it were junk, it would have been laying outside, I hoped.

This is the first Caddy I have ever built, so this may be elementary to some of you, but to me, it's a vertical learning curve.

I pulled intake and started the tear down part of the rebuild. It's greasy and grimey and has about 1/2" of dirt coated in oil.
Most of the teardown is pretty basic nuts and bolts, but there are some cool observations about the internals.
I had to knock the lifters out through the bottom. They were too badly mushroomed to get them out through the top. The cam was pretty much shot as well. I am guessing this thing didn't run very well towards the end.

Basic maintenance and oil changes were obviously not part of this engines life. I pulled the heads off, so far so good. No chunks of anything.

It has a pretty big ridge. It will probably need a minimum of .040" maybe even .060".
The heads have a history of cracking, so I figured I should get the combustion chamber cleaned up as soon as possible. I broke the heads down, removing the valves, springs etc. I bead blasted the critical areas to look for cracks.

They cleaned up pretty good. No cracks visible to the naked eye.

From the looks of the timing chain, this thing was never apart. It wouldn't have lived much longer. About a a half inch of slack.

I was surprised that they only used 2 bolts on the timing gear.
This thing really needs a caustic vat to get it clean.
I went ahead and dropped the oil pan to see if there were any catastrophic failures waiting for me.

It has a factory windage tray under the pump. Not real fancy but effective I suppose.

I did notice 2 things.
One was that the rods were marked, so this motor had to have been overhauled at least one time in its life.
The second was the odd boss on the end of the rod. It appears that maybe this was used to balance the rods from the factory. This is just an assumption on my part. They look to be drilled to remove weight.
Cadillac used forged internals, so factory balanced wouldn't be a stretch.

This thread will take a while, since I am poor and I don't get a lot of shop time these days. Just hang in there with me.

 

390 caddy = cool...

 

I didn't wanna muddy up our other Caddy thread, ya know?

 

Awesome root! Love those engines!

 

Yeah, that was interesting. The intake will more than likely be last. I want just the right induction system, so I can wait.

 

Watching this one!

 

What he said^^^^

 

Very cool. Cad engine is a great way to go for the truck. This will be interesting for sure.

 

Subscribed!


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All that grease is a pain to clean up, but usually helps keep things in good shape.
Good luck with the re-build- great story!

 

Got a machine shop picked out?

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I am thinking of using Henson racing here in OKC. He has been very helpful on some other issues. He builds a lot of the Street Outlaw guys motors.

 

Looks like fun.I`ll saddle up and ride along.
Good luck.Have fun.Be safe.
Leo

 

I am also subscribed.

 

Sweet!


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So, I made time to finish breaking down the bottom end.
My manual showed up in the mail, this is pretty good info for what it is.



I found something really odd. There was a bottle cork under the oil pan gasket in one of the holes. Really weird. Not sure why.


The bottom end all looked good. As dirty as it was, the bearings all looked really good. The only reason I think it was pulled was either oil consumption or the cam was going south. The lobes were really sharp.

I swung by the old dollar store and spent $4 for some degreaser or commonly known as oven cleaner.

I sprayed it all down and let it sit overnight. Went by the car wash the next day and hosed it off.

I couldn't resist grinding on the block. I hate casting flash. It's a weird fetish I have. This casting looks better than the Chevrolets I have done. It looks to be a higher quality. I polished on this for about 15 minutes and it shined up pretty decent. I'll put the super polish on it soon. I'll do all this before it hits the vat. I think I have found a place that has a caustic heated vat, so hopefully it will pan out.

It has some really odd freeze plugs, casting plugs, welch plugs, soft plugs or whatever you want to call them. I have never seen any like this. They ring like block material, but I am sure they were knocked in. If anyone has ever dealt with these, let me know. I am curious about them.

The rear pipe plugs look different. They must have been changed during overhaul.

The front plugs (soft plugs) look similar to the SBC. I may look into tapping them, once I find out the size.

This was kinda cool. I can run a oil pressure sender and a mechanical gauge off the same port without a ton of fittings.


I'll post more later.......

 

I ground and cleaned up the block on mine also,I did the heads and water pump as well.
Good look for not alot of time and effort.

 

Good work! I cant see in any of your pics if it has a spin on oil filter. Cadillac started the spin on filter in 1960. If it doesnt have a spin on filter it is '59 or earlier.

I rebuilt a 390 recently.....see the link in my signature for my 1959 Cad blog with lots of pics. I hope it can be of help.

 

Yeah, it's a 1962 block. Thanks, I will check out your blog.

 

Looking good sure do enjoy these engine builds. Keep up the good work!

 

Hey roothawg I've been thinking about building one of these for my Willys pickup and of course it will have a blower my biggest drawback is the availability of a custom ground blower cam any idea as to where to get one at a fair price


Chrome don't get ya home

 

Howard's told me they will grind anything for around $250.

 

I called Howard's cams today and the cam blanks that they carry can only support .327" of lobe lift. That's not total. You have to multiply that by your rocker ratio I believe to get adv lift. Someone correct me if I am wrong.

 

Cool build, I´ll be watching

 

Thanks.

So does anyone have REAL facts on the rocker arm ratios between the Caddy and the Stude? Not what you have read on the HAMB, real life numbers?

The stock 390 shows to be 1.63:1 the Stude is unknown at this point. I have read anywhere from 1.4:1-1.8:1

 

I have both Studebaker and Cad. rocker arms on the shelf; I'll throw one of each on a shaft and make an attempt at getting some reasonably accurate measurements. But it won't be until after Turkey Day...

 

Thanks. I would be intersted to see the difference.

 

Just measured from shaft centre to pushrod cup centre,then shaft centre to centre line of valve rocker face. Stude is 1.52:1 ratio, Cad is 1.68:1 ratio.
Hope this is what you were after,could be out by a bees dick but you will get the idea.