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

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

Post by RL »

Kazoom wrote:Image
Cool, now we will turn to some actual information.

Thanks for providing that photo, because it illustrates the problem with the hi-port on a street car.

The only way to get a small flow gain is to have a port that is straight and exits very high, like in the cross section drawing in the middle. The problem is that the exhaust has to be in-line with the port to preserve the small flow gain, and that means the pipes have to go upward, turn above the rocker covers, turn down against the firewall, and then turn again to go under the car. STD flow 192cfm@0.0600" - HI-PORT 225cfm@0.600".

Now imagine std exh pipes that are perpendicular to the exh plate, and that exits down like a normal street car. The exhaust starts travelling upward, but now has to make a violent turn down because of the miss matched passage. PORTED exh without the hi-port 210cfm@0.600" - HI-PORT with perpendicular exit pipes 215cfm@0.600"

The 2 heads I tested with plates that had perpendicular exits built into the plate didn't flow as good as those hi-ports. 205cfm@0.600" and 215cfm@0.600"

I could do the hi-port heads because the chassis won't let you do the normal down turned pipes because the suspension and cross member is the way, and it it's actually a competition type vehicle anyway.

Make sure you can get your pipes in before you do a hi-port, because the flow will end up being equal to a straight porting if you can't, and that totally negates all the work.
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Re: Looking for a few tips on porting 351c 4v heads

Post by RL »

Bos's5.0 wrote:
RL wrote:
4V 601hp, 2V 585hp,
Any chance you have a port picture of a 2V fully ported that you can release? I always thought they were duds because all I ever saw were people do a bunch of work and end up with 230cfm intake ports.
The trick is all in the valve size, because the correct valve size allows you to put the correct shaped SSR in to get the higher flow.
4V 2.19" valve is so big that the air has to turn under the SSR, as opposed to a 2.09" - 2.1" valve where the air has to only turn down like a in conventional port.
Blow out the bowl in every direction, Blow out the runner in all directions except the floor. And remove the pushrod restriction on the left of the port when looking at the intake flange.

Start playing with a 2.08" valve first on a test head, and see how big you can go before it starts hurting flow - the SSR shape is critical -
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Re: Looking for a few tips on porting 351c 4v heads

Post by Bos's5.0 »

↑↑↑↑ Gold nugget info.
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Re: Looking for a few tips on porting 351c 4v heads

Post by cjperformance »

There were also 4V heads that ran the 2V valve sizes.

RL, yes in the Cortina the hiports woild be great. The ports will be facing pretty much in the perfect direction for you.

Kazoom, re the 2v type heads with the rectangle intake ports, no wonder they did not continue with them! Its basically a canted valve windsor head with a 2v exhaust port and a shockingly low intake port and the same horrid short turn with the not so flash 4v type combustion chamber! Now look at the water outlet on the intake face! Those heads are aimed at producing a boss 302 with traditional windsor type intake , some better low/mid tq than the boss 302 and with an exhaust port more suitable for the cid/rpm etc. Seriously, they 'gave it to us aussies' :lol: no one here would touch that with a barge pole apart from having it on the mantlepiece as a piece for nostalgic value!
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Re: Looking for a few tips on porting 351c 4v heads

Post by RL »

cjperformance wrote:There were also 4V heads that ran the 2V valve sizes.

RL, yes in the Cortina the hiports woild be great. The ports will be facing pretty much in the perfect direction for you.

Kazoom, re the 2v type heads with the rectangle intake ports, no wonder they did not continue with them! Its basically a canted valve windsor head with a 2v exhaust port and a shockingly low intake port and the same horrid short turn with the not so flash 4v type combustion chamber! Now look at the water outlet on the intake face! Those heads are aimed at producing a boss 302 with traditional windsor type intake , some better low/mid tq than the boss 302 and with an exhaust port more suitable for the cid/rpm etc. Seriously, they 'gave it to us aussies' :lol: no one here would touch that with a barge pole apart from having it on the mantlepiece as a piece for nostalgic value!
That explains why they US gave up on the 2V - though it looked a lot worst than ours -.
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Re: Looking for a few tips on porting 351c 4v heads

Post by KnightEngines »

Flow sheet from the last set of aussie 2V's I did, they were for a street engine, 2.1 & 1.71" valves, pretty much just a pocket port with runners cleaned up & short turns done nicely, motor made just over 500hp @ 5700rpm with an rpm air gap & 830 annular on it, pump fuel, 1 3/4" tri-y headers & restrictive dual 2" system.
It was a 393 cuber, cam was 244/248 on 109.

Inlet
Flow
Lift Ported
0.1 67
0.2 131
0.3 197
0.4 238
0.5 249
0.6 258
0.65 260
0.7 262
0.75 264
0.8 266

Exhaust
Flow
Lift Ported
0.1 55.5
0.2 97
0.3 131
0.4 156
0.5 180
0.6 202
0.65 211
0.7 215
0.75 221
0.8 226

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

Post by Bos's5.0 »

Thanks for those pics.

Knightengines.. was that chassis or engine dyno?
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Re: Looking for a few tips on porting 351c 4v heads

Post by KnightEngines »

Chassis, made (from memory) around 400rwhp on a dyno dynamics (not in shootout mode) through a top loader & 9".
400rwhp on that dyno through a manual trans is around 500hp at the fly (run plenty of engine on engine dyno, then that chassis dyno - belongs to a long term customer).
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Re: Looking for a few tips on porting 351c 4v heads

Post by cjperformance »

Tony, thats pretty much the same as i do the cc 2v chambers. Simple and works really well with good detonation resistance.

RL, im not sure what year that boss windsor/clevo head is, maybe Kazoom can give us the part number/casting number. Its an attempt at fixing the boss 302's inherent low/mid range. A decent cam would have helped more!
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Re: Looking for a few tips on porting 351c 4v heads

Post by Bos's5.0 »

You Aussie guys posting those closed chamber 2V heads realize what a novelty those are here? Like $500 a set bare on Ebay.

Anyone here mess with the pro-comp Cleveland copy of a copy of a copy of a copy.....
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Re: Looking for a few tips on porting 351c 4v heads

Post by KnightEngines »

I've got 2-3 sets upstairs still, all the povo pack 302C came with them, they are not exactly thin on the ground even now!
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Re: Looking for a few tips on porting 351c 4v heads

Post by cjperformance »

KnightEngines wrote:I've got 2-3 sets upstairs still, all the povo pack 302C came with them, they are not exactly thin on the ground even now!
More plentiful than the open chamber 2v in australia!
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Re: Looking for a few tips on porting 351c 4v heads

Post by cjperformance »

Yes in "1970" they (boss 302) were fine! By todays standards the boss 302 is not real impressive, build one using some modern aussie alloy clevo heads and you get a completely different animal.

As time went by Ford knew the boss 302 / clevo 4v head was not fantastic, why would they go to the effort of casting up the windsor intake faced XE head with the same valve angles to allow for use on a boss 302 short block! They saw the XE head as possible fix to broaden the useable rpm range on the small ci engine. I'd love to see an intake port mould of that head, a wedge intake port height, narrow port, clevo intake valve angle, the short turn in them must be impressive!

Dont get me wrong, im a Ford fan and i love the old ford muscle era engines/cars. And i appreciate you posting pics of things like that XE head. Its good to see rare stuff like that ive heard and read about but never seen. Good or bad i love the experimental stuff.
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Re: Looking for a few tips on porting 351c 4v heads

Post by piston guy »

That particular XE head was designed to be a lower cost '70 Boss production engine. The poor performance , partly due to the 240 cfm air flow of the intake port, caused the program to be cancelled and the revised '70 head ( developed simultainiously) won out. A friend in the San Francisco area has a pair on a running engine making over 400 hp. Power is comparable to an original C6FE headed engine using the same components.
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Re: Looking for a few tips on porting 351c 4v heads

Post by cjperformance »

piston guy wrote:That particular XE head was designed to be a lower cost '70 Boss production engine. The poor performance , partly due to the 240 cfm air flow of the intake port, caused the program to be cancelled and the revised '70 head ( developed simultainiously) won out. A friend in the San Francisco area has a pair on a running engine making over 400 hp. Power is comparable to an original C6FE headed engine using the same components.
Intresting, lower cost boss. If thats the case im guessing they planned to use the 4 barrel sjzed exhaust manifolds that use the 2 barrel port face like we got on some of our 2 barrel clevos here.
Maybe a regular 4 barrel 302 w intake and retain the boss short block. Do you have any more info on them?
Craig.
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