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Much depends on your budget. If you want to spend less than a grand, supercharging or stroking is out of the question.

But you could do this for under a grand, and get about 320 hp and still be smooth enough your wife could drive it.

While I have the C3OZ-6250-C mechanical cam in my own car, mechanical cams are not for everyone. The C9OZ-6250-C hydraulic cam provides very similar performance.

For this upgrade, you will need:
  • C9OZ-6250-C camshaft
  • Cobra or Performer RPM intake manifold
  • Autolite, Summit, or Edelbrock 600 cfm carburetor
  • 14" open air cleaner
  • Distributor recurved to BOSS 302 specifications
  • Dual valve springs (recommended)
  • Screw-in rocker studs (recommended)
  • Heads port-matched to exhaust (or aftermarket heads)
  • 289HP exhaust manifolds or headers

This combination has been dyno tested at 323.5 hp @ 5300 rpm.

Nothing else is required. No whiz-bang million volt coil, 10mm wires, etcetera.
 
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Discussion Starter · #23 ·
At what engine compression is the above? Because i have most of those parts except the cam but I don't think that cam will get me there. I am starting with the assumption this C code engine is putting out like 175HP stock in todays standard vs the 200HP advertised they had back in the day. I can see the above with a 10 or 11:1 compression.
 

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At what engine compression is the above? Because i have most of those parts except the cam but I don't think that cam will get me there. I am starting with the assumption this C code engine is putting out like 175HP stock in today's standard vs the 200HP advertised they had back in the day. I can see the above with a 10 or 11:1 compression.
They were .030 over 289 2V pistons. Raising the compression ratio is not very cost effective, and forces you to buy the really expensive premium pump gas.

The C9OZ-C cam is the hydraulic version of the C3OZ-C, which was the cam in the 289 High Performance. The 65-67 Shelby GT350 (using the C3OZ-C) was rated at a pretty honest 306 hp, and the above combination beats that by about 15 hp, due to cleaning up the exhaust ports.
 

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They were .030 over 289 2V pistons.
@22GT Would you please elaborate on the specifics of this motor?

What heads did you port? What was the combustion chamber CC volume? What was the installed height of the pistons? What was the head gasket thickness?
 

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A few years ago I needed to replace the worn out 7 cylinder 302 in my 66. The engine was pretty lame. I didn't even bother to put a tach in the car. I have a good reman 302 but it has those awful 69cc heads. I was going to put on a set of GT40P heads I had. I still needed to do something about a cam, flat tappet motor. I was going to just use another flat tappet cam. I thought about it for a minute. It would actually be cheaper to buy a whole GT40P motor and that's what I did. I sold the P heads for $525 then bought my GT40P for $450. Sold off what I didn't need for $175. Bought a swap meet Stealth intake for $80, used Mustang 5.0 cam $60, used Edelbrock 600 $125. So even without doing the math you can see I have very little money invested. I did install a spring kit. I was going to install a free E303 cam but unfortunately it got wet at some point rendering it useless. That's why I spent $60 on the cam. I don't recall the cost on the spring kit from Alex's Parts but it included a shim kit and new valve guide seals. I did but a new flywheel and balancer but I consider them consumables anyway. The flywheel is a PRW SFI billet. While it may seem overkill, my feet are certainly worth the cost of a good set of work boots but besides that, it's drilled for both the SAE and metric 5.0 bolt pattern. This allowed me to use the free King Cobra clutch kit given to me.

I don't know how much power it makes. My thoughts were around 260. I got to chatting with someone who works in a engine shop with a dyno. He said he's dyno'd several GT40P with the Mustang 5.0 cam and told me they make right around 280hp. I can believe that. It's not some pie in the sky number and it's below 300hp. I don't know how much it really makes. What I can say, it runs very, very well! It'll put me back in the seat when I punch it. Runs much harder then my 85 5.0 t speed LX I use to have. It runs so we'll, I'm having a hard time justifying a cam swap. Broad torque curve and pulls hard to about 6000. I'd love to do another GT40P swap on something else.
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