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Dyno 351C 2v vs 4v Heads


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http://www.7173mustangs.com/thread-the-amazing-351c-4v <~~ from this classic tread..Cleveland 4v heads stock intake port was optimized for 0.600 inch valve lift.

 

thanks for that link! bookmarked. that's a lot of history in one gulp. not sure how much of it is true and it seems Pence is an evangelist for the 4V, but a lot of it does make sense... optimized for .600" lift, 7000 RPM, Nascar racing, iron crank vs steel, bottom end built to handle 7000+ rpm, drag racers vs nascar, rousch v hank the crank...lol

 

to handle 600 lift and 7000 rpm, the top end components (non-R code) for most 351C probably needed to be beefed up with conversion to studs & guide plates, dual springs, single groove valves needed to matched up a higher lift cam

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to handle 600 lift and 7000 rpm, the top end components (non-R code) for most 351C probably needed to be beefed up with conversion to studs & guide plates, dual springs, single groove valves needed to matched up a higher lift cam

 

 

Yes on all of those and a stud girdle is good insurance along with a set of Roller rockers

 

My cam has .641 lift intake and exhaust, everything mentioned above and a rather beefy set of pushrods and solid roller lifters.

 

Valve stems are undercut to improve flow, but nothing else dramatic.

 

Drag racing requires a little different set up than oval track racing, but Clevelands did pretty well in both arenas.

http://www.7173mustangs.com/gallery/1_01_07_15_8_53_18.png

 

"I love my Hookers!" and "Get some Strange" probably have a different connotation to non automotive enthusiasts!

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Wow the port plates we've always used down here in Australia look nothing like those things offered from MPG. The intake ones are a solid alloy piece that is shaped and not flat like those ones and are held in with grub screws from underneath the port. Even the exhaust ones look a fair bit different, the ones we used to use we made of thicker material and the floor would shape into the port beautifully. I'll see if I have any pics around to show the differences, because to me those ones just look like they cheaply made, and made so anybody with simple mechanical skills can just bolt them in and think they're going to make a ton of more power. Also I notice they say with their product that they will give you an extra 20hp. Whereas the ones we used to use would lift flow and airspeed well over 30% over standard 4V. A guy I know, when he had his XY GT, that was all he'd done to his heads + new Ferrea valves and associated parts for his top end rebuild. No porting, no fancy valve seat multi angling, just a good 3 angle job, and it made a massive difference to his car compared to running the standard 4V heads on the exact same bottom end. All I remember was the next time I ran into him, he was ecstatic how well it went and how his car showed up all his "chevy's are the best" mates cars and blew them off the track. He thanked me so much for all my advice, and said he wished he had listened to me years ago when I was still doing it for a living instead of listening to know it alls who told him that port plates don't work, etc.

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It sounds like you are describing what I have heard called port fillers as opposed to port plates and if so, I tend to believe they are the best mod for a 4v head, short of building a stroker motor.

http://www.7173mustangs.com/gallery/1_01_07_15_8_53_18.png

 

"I love my Hookers!" and "Get some Strange" probably have a different connotation to non automotive enthusiasts!

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