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Recently been looking into alloy heads for my holden 383, wandering what benifits the alloy has over the factory vn heads. At $4000 for yella terra heads just wandering how much extra performance you can get out of these heads, rather than porting and increasing valve size on the vn heads, Aiming for about a 500hp engine. any advise would be great. cheers
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Im pretty sure i remember reading about these in a tech article on building Holden motors. VN heads flow well from factory, and better when ported by someone knowledgable, but still dont match the flow capability and performance characteristics of the custom designed alloy heads. Weight also comes into it a little.
If you want 500hp its definitely achievable with VN heads, you just need the right combo and the right head specialist/engine builder. |
"Silly modern cars" |
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Are yella terra heads $4000 bare any better than come heads $2750 any advise opinions??? what would vn head work to the same figures be roughly worth?
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"if" i needed alloy heads, id seriously look a the COME castings, they have 3 or 4 versions depending on where youre going with the engine and how far you intend to go later.
If youre a serious tyre kicker give Sam or Issy a ring at COME and tell them what youre building and what you want it for, but be warned, dreamy and general questions about what you read on teh intehnets are often met with derision lol.
Real good people to deal with i reckon, and at the forefront of holdenv8 technology in my opinion.
11.52@115mph street trim,
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500hp is easily done with iron heads BTW, almost better off spending alloy head money somewhere else.
What manifold are you using?
11.52@115mph street trim,
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Using a tourque power single plane high rise. Have been told that it is possible with worked vn heads, but cant get an accurate price for head work cause everyone i talk to charges by the hour not job, other people have said any where from $800 up to 2000+ if your increasing the valves as well. for the higher end of the scale was weighing up the option of alloy heads.
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youll need bigger valves or the airspeed through the seat is too high, and the smaller curtain area will restrict the flow with standard 1.94s probably end up with 2.05s in the inlets, standards on teh exhaust, but probably want stainless valves in the exs What cam are you looking at to make 500? Around [email protected] will do it, and should peak around 6200rpm on the 3.75 stroker. I would seriously consider a 4 bolt conversion, leave the girdles for the ladies lol. aim for 11:1 comp on pump 98, get the manifold match ported, and the injector notches cut in. Youll do it with a 750hp double pumper, but if you dont already have the carb id use a 950hp (flows around 830cfm) Difillipo 1 3/4 four into ones, twin 3" exhaust with good mufflers. around 3500rpm 10" convertor would drive nicely and be sweet for that cam/cube combo. 11.38@117
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Not sure of the cam yet everyone i talk to gives me differnt opinions, one recomendation i was given was from camtech was a solid 248/ [email protected] and .579/.587 lift. but looking into a crane cam also.
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get the camtech solid, and ask about edge orifice lifters as well, dennis/malcolm are great to deal with and their cams are excellent. Crane 288 is a 20yr old design, COME have a version of it also that i havent used and id personally stay clear of CROW for anything but CrMo pushrods. Also, if you speak to camtech, get the lifters "coolfaced" which means they edm a precise hole from the cam lobe face to the oil band, it really helps prolong the life of the cam lobe given that they are basically splash lubed ex factory and dont tend to last too long in a holden with a decent aggressive cam. 11.38@117 Edited by user Thursday, 11 June 2009 7:55:30 PM(UTC)
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Cool faced cheers ill look into that.
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what benefits are there to getting a new cam put in.
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