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| Mac Winter 76XB351GS |
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Gday,
I know Ive posted about this before, but anyway. My cousin and I are looking at sending our 351 heads in for a mild port and polish. I know that the CHI heads will give better results but I cant justify the $$$, all I want is a bit more flow to better suit the 750holley and a few more hp, going for a mild cam later on, nothing crazy. Just want to know what kind of gains I can expect from getting the heads cleaned up and opened a little more. Also an old bloke who used to work on Falcons back in the day said to get the valve throats opened up. He drew a pic of how the valves are set up and what needs to be done. Check the pic and let me know if the valves are set up like this or if he was having me on. He said to get the valves taken out and bore the throats "A" out so it is a str8 shaft. Thanks
_________________ 76XBGS, 383c, custom crow cam, 4V p&p heads, Isky SS Valve+springs, extractors, 2.5"twins, MSD Ignition, Edelbrock intake, Forged bottom end, Barry Grant 750DP, thermo, discs, toploader, Holley fuel pump, SUPERCHARGED! |
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| Jaysen |
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they do have a lot of excess crap in there. Ive got a couple of sets of 2V closed chambers that basically have what you have drawn there.
_________________ Dima, Mitch & Jay's RPD |
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| Walker |
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A big thing on the Clevo is the dog leg in the exhaust port, you can't take it all out as it's not very thick and you'll hit the water jacket, but it makes a big difference if that's cleaned up.
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| kenny |
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Here's something to consider if you want pretty serious power that is very streetable, I have a set of 4V heads that will be getting this treatment, the guy who is gonna do them has done a few sets now & claimes that they flow close CFM to yates & CHI alloys.
Cost is approx $1400, which is not that much more than getting them reco'ed
_________________
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| Walker |
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By the look of that he's sticking port tongues in and cleaning the heads up.
They definately help with 4V, they're a pig for down low power and tongues help give it back. |
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| kenny |
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Nah, he actually mills the exhaust port off where it kicks down, then fabricates an Alloy block to replace the material that has been removed, this time though the port is not just being raised at the bottom (like plates) but top & bottom is raised by up to 3/4".
The only downside is you will have to modify you're headers or get custom made
_________________
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| Walker |
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I'll find some pics of my Clevo heads that were done by Superflow in Sydney.
The bottoms were raised and the tops were cut and all was filled with bronze... $3500 just in machining alone, but the best pair of cast iron Clevo heads i have ever seen. |
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| kenny |
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Heres my clevo thats getting the treatment! last time it made 581hp at the flywheel
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| 409Stroker |
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I dont understand when you say you cant justify the cost of CHI alloy heads but you have a suppercharger hanging off it ?? ive got CHI 3Vs that have been ported and tidied up best money i have spent and if it made that much horsepower before emagine with a set of alloys on it crypes...... bye the heads and be done with it!!!!
_________________ If you have it under control then you dont have enough power..
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| kenny |
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I'm not saying "I can't jusyify the cost of alloys" no way, would I even doubt the technical advances since 69 when my 4V's were designed, but I will have a displacement of 422-460" thanks to the siamese sleeve job done on my NASCAR block, allowing me to go oversize up to .180''.
I already have the heads just sitting there, and the 6/71 will be overdriven by 10%, so the port volume will be in my favour, 340cfm @ 20" is pretty hard to out flow. If I were to build a N/A engine I wouldn't think twice about it though.
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| 409Stroker |
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holly s**t....... i would like to see this monster of a motor do some runs ,bigcubes and supercharged mmm i want one... i hear you loud and clear..
_________________ If you have it under control then you dont have enough power..
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| kenny |
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you can convert any clevo block to a big cube combo, & you will be surprised in how it changes the characteristic of the "not so free revving" torque loaded 351, into something you have to keep you're eyes on the tacho & limit it
It is expensive to get done, but the block is bullet proof as long as the machinist brazes the sleeves together in a furnace, meaning all surfaces must be re-machined true. by the way that is a very "nice" looking package you have there. cheers kenny
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| 409Stroker |
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yer mate ive stroked my girl out to a 393 with 3Valloys H beams ,Rose race pistons sollid roller cam with 700 lift the cam produces the goods from 3200rpm to 7500rpm all crane rocker assembly funnelweb manifold 850 Demon carb all MSD altinator and dizzy C4 auto with extra clutches full manual auto 3500 stally and reverse patern shift and ive got a 150hp wet shot of nos will be finnished in next two weeks expect to have around 500hp at the treads with out gas im running 3.9 dif gears in a fully tuffened 9inch ...but we will see what the true figgers are when she hits the dyno could be less but i hope not all up she cost just over 20 thou for the build up on the donk.. there goes the house deposit lol...when she is finnished ill be posting a video so you should see her do her stuff lol as the saying goes there is no replacement for displacement.....
_________________ If you have it under control then you dont have enough power..
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| kenny |
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there goes the house deposit lol...
But lets face it you can't drive you're house to work .... can you!
_________________
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