Looking for a few tips on porting 351c 4v heads

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groberts101
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Re: Looking for a few tips on porting 351c 4v heads

Post by groberts101 »

Sheesh.. this kinda stuff always goes to the extremes. Maybe some of you guys need to read back to the OP's original intentions here? He knows that there are superior castings available, probably pretty well knew it before we all told him 20 times over in this very thread alone, but wants to fool about and learn some hard and long lasting lessons along the way.

Don't get me wrong, I like the old iron stuff. But I'm also older and more nostalgic than many gearheads so sometimes that familiar "old-school" bias starts to kick in and puts the boots to most evrything I've learned in the past 30 years of tinkering with horsepower. But luckily those hard knocks on the ole' noggin start to ache all over again the first minute I have them sitting on my bench for a quick once over. I port maybe 2 sets of iron every year for budget guys and my back hurts just thinking about the level of work required to improve these heads to match even a set of lowly Procomp's. I'll leave them to the purists and nostalgia racers stuck in the 70's and all the other sadists who like horsepower handicap's.
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Re: Looking for a few tips on porting 351c 4v heads

Post by wyrmrider »

"Glidden is great"
Who assembled many many engines with WHITE GREASE
and wondered why the bearings coaked up and spun?
I remember the quote
"blew all those motors for YOU"
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Re: Looking for a few tips on porting 351c 4v heads

Post by wyrmrider »

X2 on RL's post above
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Re: Looking for a few tips on porting 351c 4v heads

Post by RL »

But you could also say that the SVO is just an Alum a copy of the original head.

What it seamed like was that the US went Windsor way, but over here we only got the Clev so we keep working on them. People got sick of filling 4V's so Con and John had the idea to make an aftermarket head Clev with the correct sized port and modernise it.

There is nothing wrong with the 4V if you put tongues in the inlets, but the exh is too much work unless you're very keen.

If he wants to do it I'll give him advice.

Sure you can do the exh hi-riser plate fast, if you have done them before, but a first timer using a billet alum plate and hand turned up head bolt sleeve/dowels, you better allow 15 hours.

Look at the last exh port on the picture and see where the exh floor has a tiny flat section before the head cutout, that is where you have to watch for cutting through and hitting water.

Image
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Re: Looking for a few tips on porting 351c 4v heads

Post by cjperformance »

In the area RL pointed out you have about .240" +/- core shift, corrosion, porosity etc etc.
P.s. the cutaway pic is of a 2 barrel clevo ex port but casting thickness is nominally similar here.
_IMG_000000_000000.jpg
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Re: Looking for a few tips on porting 351c 4v heads

Post by Bos's5.0 »

I was messing around looking up info on 460 Ford heads and what they are doing about exhaust issues, and I found a nugget here and there. One of those was someone mentioned they had first hand knowledge of 800+hp iron cobra jet headed big block that had barely 200 cfm exhaust ports.

In reality, just how much is all this exhaust BS good for? Sounds to me like you are much much better off paying most of your attention to the intake side.

Which would you rather have.... 300/220 @ .600 or 350/190 @ .600
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Re: Looking for a few tips on porting 351c 4v heads

Post by piston guy »

The Iron 351C 4V head never looks good on a flow bench and never will. Once you realize it is impossible to duplicate operating conditions on one you'll quit bench testing it. "Proper" camshaft timing (short duration high lift intake and longer duration lower lift exhaust) as well as a good header design , power will "magicaly" be there. I did a 408C with iron heads ( no stuffers) 12-1 roller cam , ti valves and a Holley strip dominator intake that was a bit over 600 hp 20 years ago. I also built a short deck (8.2) 351 with Boss heads that made 616hp. 14-1 roller, ti valves, dual fours, roller cam etc.
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Re: Looking for a few tips on porting 351c 4v heads

Post by RL »

cjperformance wrote:In the area RL pointed out you have about .240" +/- core shift, corrosion, porosity etc etc.
P.s. the cutaway pic is of a 2 barrel clevo ex port but casting thickness is nominally similar here.
_IMG_000000_000000.jpg
I remember the 4V being a little bit thinner than the 2V, more like 0.180"

If I visit where I used to work I will get a photo.
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Re: Looking for a few tips on porting 351c 4v heads

Post by cjperformance »

Im kind of wondering why the constant reference to the 'aussie copy' ?
Is the A3 the holy grail of clevo heads!? Can there be no other head ever made for a clevo that could possibly be better than the A3 :lol: without being referenced back as a 'copy' !
Everyone got ideas from everywhere else for any given product.
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Re: Looking for a few tips on porting 351c 4v heads

Post by Bos's5.0 »

cjperformance wrote:Im kind of wondering why the constant reference to the 'aussie copy' ?
Is the A3 the holy grail of clevo heads!? Can there be no other head ever made for a clevo that could possibly be better than the A3 :lol: without being referenced back as a 'copy' !
Everyone got ideas from everywhere else for any given product.

Its been said that the Cleveland is a copy of the big block Chevy heads...So maybe the Chevy guys need to get in here and start ripping on the A3 lovers.
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Re: Looking for a few tips on porting 351c 4v heads

Post by cab0154 »

Bos's5.0 wrote:
cjperformance wrote:Im kind of wondering why the constant reference to the 'aussie copy' ?
Is the A3 the holy grail of clevo heads!? Can there be no other head ever made for a clevo that could possibly be better than the A3 :lol: without being referenced back as a 'copy' !
Everyone got ideas from everywhere else for any given product.

Its been said that the Cleveland is a copy of the big block Chevy heads...So maybe the Chevy guys need to get in here and start ripping on the A3 lovers.
Right. other than having a 4.38" sbf bore spacing, the Cleveland is a direct copy of the 4.84" bore space bbc. :---)
"Anyone who thinks the low RPM engine will be faster just does not have as much experience as the rest of us" -The late, great Joe Sherman.
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Re: Looking for a few tips on porting 351c 4v heads

Post by clevo »

Bos's5.0 wrote:
cjperformance wrote:Im kind of wondering why the constant reference to the 'aussie copy' ?
Is the A3 the holy grail of clevo heads!? Can there be no other head ever made for a clevo that could possibly be better than the A3 :lol: without being referenced back as a 'copy' !
Everyone got ideas from everywhere else for any given product.

Its been said that the Cleveland is a copy of the big block Chevy heads...So maybe the Chevy guys need to get in here and start ripping on the A3 lovers.
You have to be kidding! Have a good look at the BBC chamber and then the long and short intake runners totally different than a Cleveland 4v head.
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Re: Looking for a few tips on porting 351c 4v heads

Post by BCjohnny »

It's a lot more than just bore spacing. Look at how the inlet ports discharge into the cylinder for one :wink:
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Re: Looking for a few tips on porting 351c 4v heads

Post by smeg »

As I have posted before, please don't say that all the other makes heads have copied the Ford canted valve head. Have a look at the Chev canted valve head in Smokies book that somehow looks strangely like a Cleveland head? Except this head was out and being used before the Cleveland came on to the showroom! So did Ford copy Chev? and not the other way around???

I have ported heaps of 4V heads over the years, some with fillers, some without, for their day they were a great head. But to say they are anything similar to todays heads is handling the truth a little carelessly.
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Re: Looking for a few tips on porting 351c 4v heads

Post by user-23911 »

It was the same bloke designed them both.
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