What to do to 351c 4v heads?

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72 Mach 1, Q code 351CJ, 4 speed.
When I go to the machine shop what all do I want them to do to my heads if I go this route instead of running aluminum's?  List please. :D

What porting should I do before taking the heads to the machine shop?  gasket match intake and exhaust ports?  Smooth out exhaust ports?  Any polishing for the intake ports?

 
Thanks! I am still trying to decide if I want to go aluminum or keep the iron heads. Im guessing it will be about a $500 difference if I go edelbrocks or stick with machining the iron heads. Any thoughts, advice??

 
Minor port cleanup, do not polish the intake ports, 3-angle valve seats. Minor roughness creates turbulence which helps to mix, and keep mixed, the fuel and air particles.

Have the heads machined for adjustable rocker arms, have the valve guides checked for wear and proper clearances and replaced if needed. Knurling the guides is OK for minor wear. Have the valve guides machined for positive valve seals.

 
I would say if you want to modify the performance, go with the Aluminum heads. 

 I really agree with the posted article above, in spite of claims of professionalism, the 4V head is kinda misunderstood.  Look at it this way, the Boss 351 engine is known for being a high performance Cleveland engine.  I don't believe there is any difference in the ports on the quench chamber 4V vs the Boss Heads.  The performance comes from the camshaft, the carb, the pistons, and the rear gear ratio.   So why go custom on such a well engineered head?  I have actually heard that the obvious"hump" on the exhaust side that all hot rodders want to grind away is actually a benefit to exhaust gas flow by creating a converging-diverging nozzle effect.

kcmash

 
Thanks!  I am still trying to decide if I want to go aluminum or keep the iron heads.  Im guessing it will be about a $500 difference if I go edelbrocks or stick with machining the iron heads.  Any thoughts, advice??
Exactly what is your goal?

Do you want more bottom end?

Do you want less bottom end but more rpm on top?

I wouldn't touch the ports unless you are an experienced head porter.

You will get the most overall power from chi heads. If you want big time power, you should buy chi heads.

 
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I went through this dilemma with my CC 4Vs. After reading and researching a lot i decided to keep the casting stock except for the valve angle job and machined for rocker screw in studs. I also cleaned and smoothed the chambers a little.

Sent from my SAMSUNG-SM-G930A using Tapatalk

 
+1 on chi's they're what I'm running, although mine are 2v. If you wanna see them you're close enough that it wouldn't be a big deal.

 
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If you want to make the low end a bit better, go for some Aussi 2V CC heads.  They have the best of both US 2V and 4V heads.

The only real difference between the 2v heads you have and the Aussie heads is the combustion chamber. To take advantage of the Aussie closed chamber you will need pistons that create a quench area, doing this and keeping the same compression you currently have may allow you to decrease your octane requirements. A good quench area has the ability to make the motor more resistant to knock.

Then theres also these.... if you really want something killer.....

http://www.chiheads.com.au/product-category/heads/ford-cylinder-heads/3v/

 
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Thanks!  I am still trying to decide if I want to go aluminum or keep the iron heads.  Im guessing it will be about a $500 difference if I go edelbrocks or stick with machining the iron heads.  Any thoughts, advice??
Exactly what is your goal?

Do you want more bottom end?

Do you want less bottom end but more rpm on top?

I wouldn't touch the ports unless you are an experienced head porter.

You will get the most overall power from chi heads. If you want big time power, you should buy chi heads.
It will be a cruiser, occasional trip down the strip.  I want low end power

+1 on chi's they're what I'm running, although mine are 2v. If you wanna see them you're close enough that it wouldn't be a big deal.
WOW!  You are close.  I work in uptown Charlotte.

I am running AFD SP4V Heads and they are very comparable to the CHI 3v heads.  I love them and they make monster power.  

https://www.afdheads.com/collections/cleveland-heads/products/afd-sp4v-3v-bare-alloy-cleveland-cylinder-heads?variant=34022411022
Looks like these are almost $1700 per head.

 
Thanks!  I am still trying to decide if I want to go aluminum or keep the iron heads.  Im guessing it will be about a $500 difference if I go edelbrocks or stick with machining the iron heads.  Any thoughts, advice??
Exactly what is your goal?

Do you want more bottom end?

Do you want less bottom end but more rpm on top?

I wouldn't touch the ports unless you are an experienced head porter.

You will get the most overall power from chi heads. If you want big time power, you should buy chi heads.
It will be a cruiser, occasional trip down the strip.  I want low end power
With this info, I'm going to say you should skip the aftermarket heads, have yours machined as recommended, and get a custom ground cam that matches George Pence's recommendations on the links I provided to the Pantera board. He has guys getting up to 450hp out of a relatively stock 351C-4V with a custom cam and excellent low end power. The 4V head has unique cam requirements because of the huge valve size, what works on an 351W or a 429 does not work on a 351C. While the Pantera can have a better exhaust layout, even 350-400hp is very respectable on the street. Rule of thumb with cams, when in doubt, go with the smaller grind.

 
Thanks!  I am still trying to decide if I want to go aluminum or keep the iron heads.  Im guessing it will be about a $500 difference if I go edelbrocks or stick with machining the iron heads.  Any thoughts, advice??
Exactly what is your goal?

Do you want more bottom end?

Do you want less bottom end but more rpm on top?

I wouldn't touch the ports unless you are an experienced head porter.

You will get the most overall power from chi heads. If you want big time power, you should buy chi heads.
It will be a cruiser, occasional trip down the strip.  I want low end power

+1 on chi's they're what I'm running, although mine are 2v. If you wanna see them you're close enough that it wouldn't be a big deal.
WOW!  You are close.  I work in uptown Charlotte.

I am running AFD SP4V Heads and they are very comparable to the CHI 3v heads.  I love them and they make monster power.  

https://www.afdheads.com/collections/cleveland-heads/products/afd-sp4v-3v-bare-alloy-cleveland-cylinder-heads?variant=34022411022
Looks like these are almost $1700 per head.
No that's a set of 2.

 
Do everything that Hemikiller said and get a good intake like a Blue Thunder or an AirGap along with a good carb and some 3.50 - 3.70 gears. You’ll have a blast on the street and be respectable at the strip without breaking the bank. You can always add more later. Plus if you go with much more hp then you will need to start beefing up the rest of the car to handle it.

Good luck with whatever you decide to do  :)

 
yes, gearing will increase the acceleration rate. i mentioned this on somebody's thread a few days ago.

if you want faster acceleration, the most effective things to do are either install a numerically higher gear ratio or increase the engine displacement.

in general, the bigger the cam, the numerically higher the gear ratio must be for a street car to compensate for the loss of low end power (not a land speed record attempt car).

if you change the ratio by 2 steps, it will be very noticeable but not a huge day and night difference. if you change it by 3 steps it will be a day and night difference, however, of course the engine will rev more per each mph you drive so without an overdrive trans. 3:50 gears are typically the numerically highest ratio one should go and 3.40 is a good ratio for a performance car that sees a fair bit of freeway driving.

What are your rear gears?

 
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Thanks!  I am still trying to decide if I want to go aluminum or keep the iron heads.  Im guessing it will be about a $500 difference if I go edelbrocks or stick with machining the iron heads.  Any thoughts, advice??
Exactly what is your goal?

Do you want more bottom end?

Do you want less bottom end but more rpm on top?

I wouldn't touch the ports unless you are an experienced head porter.

You will get the most overall power from chi heads. If you want big time power, you should buy chi heads.

What are your rear gears?
I'm guessing the stock gear 3:23???

 
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Here he covers the entire engine.

https://pantera.infopop.cc/topic/sticky-3-351c-basics-and-performance-tuning

351CJ specific

https://pantera.infopop.cc/topic/cobra-jet-unleashing-the-performance-capabilities-of-351-cleveland-engines-with-open-chamber-4v-heads-q-code

Post with cam specs etc

https://pantera.infopop.cc/topic/questions-regarding-george-s-275-285-custom-street-cam-profile

Might be worth a shot to join the forum and ask George for a specific recommendation for the Mach 1, considering the intake and exhaust differences over a Pantera.

-

 
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