Camshaft replacement, current cam specs unknown

[Peachy Bronco]

Looking for recommendations on a replacement cam for my '72 Bronco. I bought this a few years back with zero history on the engine, and I don't know a ton about engine build specs myself.

The project started as a simple timing chain replacement with my in house farm mechanic (who knows old engines well, used to rebuild and build high performance engines). After opening things up, he found a rocker that wasn't lifting, and eventually found 4 badly worn cam lobes. We have the old cam out, but don't have the tools to figure out the specs on the old cam that came out. I don't know if the block has been overbored or not.

Current Setup:

• Block: 302 ci (probably original, unknown bore)
• Heads: World Products Windsor Sr. cast iron (5304D 0007-119)
• Carb: Holley Brawler 600 CFM
• Trans: NP435 4-speed manual
• Gears & Tires: Stock gears (likely 3.50s) with 33" tires
• Old Cam: Cast CWC / EP15, end stamped Z21.
• Firing Order: Standard 302 (1-5-4-2-6-3-7-8)

It ran smooth before the teardown. Ran well and consistent for the past 4 years, and I'm not sure if I've been leaving power on the table or not. This is strictly a street driver/cruiser. Looking for torque and snappy throttle response.

My "internetting" led me to a COMP XE256H (31-234-3) cam, not sure if that's appropriate or not.


Appreciate any insight and can provide more details if needed. Thank you!

 

[ba123]

Well, Google Search AI has gotten pretty good and I put that cam line and your engine and came up with this:
AI Overview

searched: "Cast 302 camshaft CWC / EP15, end stamped Z21"

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Based on the markings provided, you have a hydraulic flat-tappet camshaft designed for a Small Block Ford Windsor (221, 260, 289, 302, or 351W) engine. [1, 2]
The identification markings break down into two parts: the raw core casting and the final machined grind.

1. The Casting Markings: CWC & EP15

• • CWC: This stands for Campbell, Wyant and Cannon, a famous American industrial foundry. They manufacture raw cast iron camshaft blanks (cores) for the vast majority of original equipment manufacturers (OEMs) and aftermarket camshaft companies (such as Comp Cams, Crane, Melling, Elgin, and TRW). [1, 2]
  • EP15: This is the foundry's internal core part number. An EP15 casting is specifically designated as a flat-tappet camshaft blank meant to be machined for Small Block Ford Windsor V8 engines. [1, 2]

2. The Machined End Stamping: Z21
Because thousands of different camshaft performance profiles can be ground onto the exact same raw EP15 core, the casting numbers won't tell you the performance specifications. The Z21 stamped on the flat end face is what actually identifies the finished grind profile. [1, 2, 3]

• • The Profile: In aftermarket coding (often traced back to vintage Wolverine/Blue Streak, Melling, or generic white-box grinds), a "Z" prefix or specific Z-code typically designates a mild-to-moderate performance street upgrade.
  • General "Range B" Specs: For typical catalog flat-tappet upgrades ground on this specific family of blanks, it generally features a mild duration (usually around 195° to 210° duration at .050" lift). These cams are designed for strong low-end torque, a smooth-to-fair idle, and a power band ranging from idle up to roughly 4,000–4,500 RPM—perfect for stock replacements, street cruisers, or light towing. [1]

To help pinpoint the exact lift and duration of your Z21 grind, do you happen to see any other letters, logos, or stamped numbers on either end of the shaft? (Look for markings like CC, M, TRW, or a hand-etched serial number). [1, 2, 3]
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I would compare those specs by measuring your cam lobes and see if that's correct and decide from there.

 

[73azbronco]

Do what the old guy recommends.

Non roller sounds like, call comp and ask their recommendation. I suppose you want as close to what you had?

Break in properly, knowing newest oils do not support non roller style valvetrains.

 

[Peachy Bronco]

Thank you all. The only other markings on the cam are stamped into the casting, not on the ends. All the markings in the casted part: K1, C5, CWC, EP 15, 10, and D5. Only Z21 on the end.

And yes, looking for a similar cam. Or any suggestions as well if it would better suite my setup.

I'll measure the camshaft lobes shortly and post it.

 

[73azbronco]

Call comp cams.

 

[rjrobin2002]

Research for days on how to break in cams, all my ford small block groups with very knowledgeable motor guys have frequent failures due to modern oils and modern cam/lifter materials not being as good quality and failing on break in.

 

[bronco italiano]

https://www.camresearchcorp.com/cam-king-camshaft-break-in/

 

[Peachy Bronco]

The break in procedure and materials is one thing my mechanic has been stressing big time.

Going to reach out to comp cams tomorrow. Thanks all.

 

[73azbronco]

and research how modern oil left flat tappet tech behind, you will need special oil or additive all the time, not just for breakin

 

[bronco italiano]

I use Swepco 306 engine oil in my old school hydraulic flat tappet engines. Most Porsche 356/912 owners use Swepco 306

 

[Broncobowsher]

The World Products Heads are probably loaded with some stiff valve springs that are better matched for roller cams. That may part of the flat tappet lifter failure. Part of picking a cam is also pairing to the valve springs.

 

[Bruners4]

If you are planning on a new cam and lifters, why not consider a retro-fit roller cam setup?

 

[Grey owl]

Don't go to wild, i put in a hydraulic Comp Cams RV cam with 260 duration 494 lift, its a common grind gives you good bottom end and a very distinctive idle, you can tell right away it has a aftermarket cam. I bought cam lifters and push rods.
Follow the break in instructions closely.

 

[Peachy Bronco]

If you are planning on a new cam and lifters, why not consider a retro-fit roller cam setup?

I'm a little torn between flat tappet and roller. I think I'd prefer flat tappet for it's simplicity of re-install, but roller lifters sound more robust in the long run?

Would the heads need to be pulled if I put some retrofit roller lifters in? That would probably steer my decision.

 

[Grey owl]

I'm a little torn between flat tappet and roller. I think I'd prefer flat tappet for it's simplicity of re-install, but roller lifters sound more robust in the long run?

Would the heads need to be pulled if I put some retrofit roller lifters in? That would probably steer my decision.

Heads don't have to come off to install roller lifters, but do you have a roller block. You cannot just slip a roller cam and lifters in a vintage block. If you choose a roller set up you should change the valve springs for sure. If you plan to modify the block to accept a roller cam the engine has to come out and be torn down to do those modifications correctly.

 

[ba123]

Heads don't have to come off to install roller lifters, but do you have a roller block. You cannot just slip a roller cam and lifters in a vintage block. If you choose a roller set up you should change the valve springs for sure. If you plan to modify the block to accept a roller cam the engine has to come out and be torn down to do those modifications correctly.

Isn't the difference between a roller block and non-roller block just the spider tray that keeps the lifters straight?

Can't you just use the linked/connected lifters? I remember doing an engine like that way back. Why would you need to tear it down? Might be right that springs would be better changed, but just thinking out loud here. Been decades since I've thought about something like that.

 

[Peachy Bronco]

Thanks Grey. It's not a roller block, and if it takes breaking the engine down to install them I'll just go tappet. My research shows that there retrofit kits that let you drop in rollers, and you can do that without having to drill and thread holes for the lifter retainers?

Thanks for everyone's input, I think I'm going to keep it simple go with flat tappets and see how she runs for the next few years. If they happen to fail again prematurely, I'd rather put my money towards a new crate engine. Also going to look into that Cam King break in, would be pretty sweet!

I was on hold with Comp Cams for about 45 minutes with no answer, so no help on that front.

 

[Grey owl]

Isn't the difference between a roller block and non-roller block just the spider tray that keeps the lifters straight?

Can't you just use the linked/connected lifters? I remember doing an engine like that way back. Why would you need to tear it down? Might be right that springs would be better changed, but just thinking out loud here. Been decades since I've thought about something like that.

There are certainly options, i personally would use the recommended spider kit from comp cams. I would want the the block out for drilling an tapping. But thats just me.

 

[Broncobowsher]

The factory spider and dogbone style roller blocks have taller lifter bores. I don't think you can retrofit factory rollers into an old block. Leaves the retrofit roller lifters as your option.

Otherwise there wouldn't be a need for a retrofit lifter

 

[bronco italiano]

I'm a little torn between flat tappet and roller. I think I'd prefer flat tappet for it's simplicity of re-install, but roller lifters sound more robust in the long run?

Would the heads need to be pulled if I put some retrofit roller lifters in? That would probably steer my decision.

Quality flat tappets, properly broken in, and good oil will last a LONG time. The issue is finding a company that makes high quality tappets and roller lifters for that fact. I put the Comp HE206/206 in my buddy's bronco with 302 and it is a very nice low end cam