351C where to start?

There's not a whole lot to decode on that vin. Its only a partial. I think you already got the year-1973 and the plant was Atlanta. The rest is the sequential car number it came from. There were a handful of cars that came with a 351C, made in Atlanta in 1973. That could possibly be a ranchero or maybe a gran torino?

Nothing about that suggests that the block is not worth the effort. You may be dealing with a rebuild motor, or somebody could have pulled a complete motor out of a different car to plop in.

I'm not sure about the engine block casting letter "A".
If that motor is otherwise good, it probably should be a 4 bolt main, not that the extra bolts actually do much, so could well be worth rebuilding to whatever spec you want, keep it stockish or stroke it.
I'm definitely not the engine guy around here, so I'm sure others will chime in to help out.
One thing is for sure, you don't have the original motor in there.

Block Casting is D2AE-CA
Production Date: 2k26 (26 September 1972?)

According to https://www.enginelabs.com/engine-tech/a-guide-to-ford-v8-engine-block-casting-numbers-1952-1996/ D2AE-CA – 1972-1974, 1971-1974, 351 Cleveland small-block, 4-bolt mains, High Output, Cobra Jet, Boss

I know I need to look in the pan to verify 4 bolt main but that's cool. So how do I figure out if I'm working with a high compression 72 HO or a detuned 73 CJ? I'm really kicking myself for not getting head casting numbers. I guess I can use borescope to peak in the oil drain to verify 4 bolt, peak in the spark plug hole to see flat or dished pistons, maybe be able to tell if open or closed chamber heads (but guessing from production date probably open chamber)?

I know this could all be a moot point if the engine was rebuilt before and the only absolute way to tell is to tear the engine apart; just trying to get as much info as possible to figure out where to steer this ship. Next up is to order the timing set and try to get it running correctly. Any thing else I should order or be on the lookout for while I'm in there?

Edit: I am kinda getting hung up on whether this is the higher compression engine or the low output 73. How big of a difference is it really? I am not ready to do a full engine overhaul so just hoping im starting with a better foundation.

351mach1,
The 1972 HO engine (as delivered) should be a solid lifter engine and therefore (should ) have screw in rocker studs and adjustable rocker gear with open chamber heads.
The CJ (should) have hydraulic camshaft, pedestal rocker arms and open chamber heads.
Boilermaster

I have a theory as to why nearly all 72-73 351C motors had 4 bolt mains;
As ALL the blocks cast could be drilled and tapped for the extra bolts, Ford produced way too many 4 bolt caps. Only certain 70-71 351C blocks got the 4 bolt option. The M code was only 2 bolt for example.
SO, as they had all these extra caps on hand and as the production line was already set up to add the extra 5/16-18 tapped holes, why not use them up.
From what I understand, the smaller bolts are there only to stop or reduce fretting, sideways movement, so do little or nothing to add strength. The main bolts hold it all together.
As for your motor, for now, get it running and worry about what's in it later. An option might be to pick up a 351C block and build your own motor later.

While waiting for the timing set to arrive, I wanted to keep making progress: I stuck a bore scope down in a spark plug hole and I am about 95% certain this engine is a 74 CJ. The picture wasn't the easiest to decipher but there appeared to be dished pistons and open chamber heads. No surprise there really. I am kinda bummed that I didn't know what I was buying but it's all part of the game I guess!

The Chinese garbage sourced from the local auto part stores is really disappointing. Wasted 2 nights of my life on trash "refurbished" starters. Is there anywhere to source quality OEM starter, alternator, distributors? I guess I can take solace in the fact that I can replace these parts as much as I want with their "lifetime warranty"

I wanted to eliminate as many potential problems as possible to ensure everything is working correctly. The Duraspark currently installed was a total mess so I bought a new duraspark wiring harness, box, and ignition coil. I am struggling to find the correct distributor that fits under the Ram Air. I will be making separate posts pertaining to the duraspark conversion and hacked wiring harness. I will return the Pertronix system I bought and stick with the duraspark.

With the fresh ignition system, I got the ol gal to fire up! She was kicking back a little bit at first (probably didnt help that it was 35 degrees out) but once she warmed up, she idled and revved quite nice!! I even took her for a victory lap around the block. Pretty excited about that!!

So far I replaced the intake manifold, carburetor, and ignition system. The original complaint of backfiring and hesitation while driving is gone. The car isn't nearly as peppy as I would have expected and I am wondering if that is still a symptom of the timing chain or more so engine and transmission combo. Since it currently runs, drives, and stops, I think I am going to shift focus to getting it legally inspected and registered before diving into the timing chain. I will follow up with this thread when I do the timing but for now I think its time to start a build thread and ask a few other questions that are probably best saved for their own threads.

I really appreciate all of your responses. Keep em coming and I'll keep posting!

Wow, so glad you got it fired and running as well as a victory lap around the block.
IF the new manifold is the same height as original where the dist. goes (it should be!) then the DuraSpark ought to fit with the Ram Air cleaner. But then of course, is the height of the carb off the manifold the same. I've got no experience with this, so just my logical thoughts, but as far as I know, the DuraSpark is pretty much the same as a points dist. size wise.
Also I believe the 73 351C did have dished pistons and open chamber heads. There was no 351C in 74, maybe just a typo there.
Anyway congrats on the progress.

Stanglover said:

Also I believe the 73 351C did have dished pistons and open chamber heads. There was no 351C in 74, maybe just a typo there.

Click to expand...

I have a million tabs open right now from all the research I have been doing but I read somewhere that the Ranchero and Gran Torino came with the 351C CJ and Duraspark beginning in 1974 so I am making the conclusion/assumption (ass out of u and me) that the whole kit and kaboodle was just swapped from a 74 Torino/ranchero which I think makes the most sense. I could be very wrong though as I am brand new to this...

I will be posting a separate thread about my Duraspark debacle...please stand by

351mach1 said:

I have a million tabs open right now from all the research I have been doing but I read somewhere that the Ranchero and Gran Torino came with the 351C CJ and Duraspark beginning in 1974 so I am making the conclusion/assumption (*** out of u and me) that the whole kit and kaboodle was just swapped from a 74 Torino/ranchero which I think makes the most sense. I could be very wrong though as I am brand new to this...

I will be posting a separate thread about my Duraspark debacle...please stand by

Click to expand...

Yeah you could be right.

There's a company called Performance Distributors who build DuarSpark distributors to specifications. It looks like the current price is $309 US, BUT 3-4 months lead time.

Stanglover said:

There's a company called Performance Distributors who build DuarSpark distributors to specifications. It looks like the current price is $309 US, BUT 3-4 months lead time.

Click to expand...

These guys are another source for duraspark distributors set up for your specific application: http://parklandautomachine.com/home

Stanglover said:

There's a company called Performance Distributors who build DuarSpark distributors to specifications. It looks like the current price is $309 US, BUT 3-4 months lead time.

Click to expand...

This is exactly what I am looking for! Thank you!

@Sheriff41 I'll also look into that

Thanks everyone!

My thoughts would be a bit further down the road so to speak. I think in your situation, I would decide what I want from or for the engine. Keep it and build as you like, then decide on timing needs. Or find another more correct 351C block, they're pretty much all the same except for 2 or 4 bolt mains or the earlier blocks had oil drain holes at the back of the block. Ford changed that to a (crude) hole at the front of the block for the 71 motors and on. Then there's head choices and that's a hole different subject.
On your current block, and here I have no direct experience, is there a raised web on top of the block near the distributor hole. I believe the 351 M block has this and is an easy identifier. A quick google search for Ford 351M engine show this web. It looks like it's about 1" high.

I realized I needed way more parts to correctly complete the timing chain job than I thought. One item is the harmonic balancer. I have a question about it:
-How tight should the new harmonic balancer be on the crankshaft? The first one I bought had about 1/16" of play while sliding onto the crankshaft. I figured that it had to be the wrong part so I bought another one. This more expensive one is slightly tighter at the end of the crankshaft but it still slides right to the front seal with no resistance. When I slide the old HB back on the crankshaft, I hit resistance about 1/4" before the front seal where I would need to start using an install tool. I have never installed a HB on a 351c so would love some of yalls expert advice.

This is the first one I tried: https://www.summitracing.com/parts/PBB-PB1082N

Second one: https://www.summitracing.com/parts/RNB-594-277

As long as your balancer is a press fit when fully installed, you'll be fine. All the balancers I've done do simply slide on some before they have a tighter fit. Make sure the top of your key is parallel with the crank.

This doesn't seem right to me...

351mach1 said:

This doesn't seem right to me...

Click to expand...

Provide a couple good photos of the balancer's inside diameter. Wobbling the balancer to start it on is normal before pressing it home; but would like to see the i.d. to further comment.

I test fitted it with the installer and it went on tight. Just surprised it's so sloppy at the start

Made a lot of progress today. The timing chain definitely needed to be changed and likely was causing some of the running issues. Check out the before and after vids! I could have had it all buttoned up today but I am waiting on a new timing cover as this one is too pitted for my liking. I threw the old cover back on just to keep dirt out as I probably wont get the cover until Thursday. The new timing set is in and I chose to advance 4 degrees which [assuming this is a stock 74 CJ] I believe puts me back at the stock 1970-71 351c timing. I am pretty excited to get this back together and see what it feels like to go from essentially no power with a huge flat spot to fresh timing chain advanced 4 degrees, brand new Duraspark II ignition, Edelbrock performer intake, and Holley Street Warrior 600 CFM carb.

I thought I was looking at a 4 bolt main but on closer inspection it appears I am mistaking the oil pump bolt as a main bolt and the block appears to actually be just 2 bolt mains.
View attachment PXL_20241203_175532018.mp4
View attachment PXL_20241203_204022485.mp4

Remember to put the oil slinger ring back on the crank snout, cupped side out, to assist in keeping the timing cover seal from seeping, before you put the plate back on the block.