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| new head for the /six what to do? https://slantsix.org/forum/viewtopic.php?t=42904 |
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| Author: | deathly_hallows [ Wed Dec 15, 2010 8:50 pm ] |
| Post subject: | new head for the /six what to do? |
ive got a new head for my six and im not sure how i want it machined i eventualy would like to put a small turbo on it eventualy but dont want to have to change anything else at the moment what would be good specs? |
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| Author: | Josh P [ Fri Dec 17, 2010 2:23 am ] |
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It is generally recommended to shave as little as possible from the head when using a turbo. So that leaves larger valves (the popular sizes are 1.70 & 1.44, I believe), hardened seats, and some porting as the common suggestions. And a turbo would benefit hugely from all of these. Also, its been said that the latter style heads (without spark plug tubes) are able to hold their gaskets better and are highly recommended for turbo builds. You will also want to make sure to get the head shaved just enough to ensure it is straight and true (might consider doing the same for the block since it will be a turbo build). |
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| Author: | wjajr [ Fri Dec 17, 2010 7:58 am ] |
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Turbo engines need low compression in order to accept boost. Also over sized valves and enlarged exhaust systems aren’t as important to performance improvement as for a naturally aspirated engine. You will have to make a decision; performance from a tweaked head with improved flow, and a higher compression ration from shaving it, or a mostly stock head & compression while waiting to cobble up a turbo charger. If were me, I would develop one head to use until the turbo is ready that is shaved, ported, and has over sized valves for some additional performance, and a stock head with a valve job, ported, and ready to go once a turbo can be installed, which is not an easy task, unless you are a good fabricator… Having that second head on hand may prove to be handy. |
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| Author: | deathly_hallows [ Fri Dec 17, 2010 2:22 pm ] |
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i have the original head on it with a blown valve and a spare laying around i just got a week ago i was having the new one machined to increase compresion up to about 8-9 from 7 ish to make it feel stronger than my 4 cylinder i want to increase the hp to around 300 by the time its done and not to offend someone but why /6 over just putting the 318 i have? |
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| Author: | Josh P [ Fri Dec 17, 2010 2:52 pm ] |
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Quote: not to offend someone but why /6 over just putting the 318 i have?
I believe the 318 HP would be rated at 170 @ 4000RPM and the Slant6 225 is rated at 145 @ 4000RPM, so you loose only about 25 peak HP. While torque is rated at 260 @ 2500RPM (318) and 215 @ 2400RPM (225).If you go with the slant you will have better fuel economy and similar performance numbers. Also, it is cheaper to shave 1 head off a slant than the 2 heads off a 318, so you will could easily get more bang-for-buck when talking about head work. Also, I think there is something to be said about the torque both engines produce, but I'll leave that to someone more knowledgable. |
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| Author: | Evilsizer [ Fri Dec 17, 2010 7:13 pm ] |
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i always did like the add-age "six in a row make it go!" also between the two you need to look at how much they weight as well. the slight HP/ft lbs increase worth the added weight overall vs the /6. would the vehicle really feel that much different performance wise with a 318 vs /6? |
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| Author: | wjajr [ Sat Dec 18, 2010 6:17 am ] |
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Small bock V8’s (later version, LA 273, 318, 340, 360) are close in weight** to a slant six, big blocks add 300 plus pounds over a slant. ** From Alpar The A engine was produced from 1955 through 1966. The LA, introduced in 1964, had the same basic design but was very heavily modified. The lightweight ("L" A) or thin-wall casting and heads saved around 50 pounds; the wedge-shaped combustion chamber was much smaller than the A engines’ poly heads, greatly reducing the size and allowing the first LA engine (273 V8) to fit into the small Valiant. The LA's valves were simpler too, saving money and size. The 273 ended up being only fifty pounds heavier than the 225-cid slant six. Years ago I had a 273 V8 1967 Dart with three on the tree, it was slower than my present slant Dart. I’m sure that my present slant build would walk a stock/ unmodified 318 without much trouble. |
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| Author: | hantayo13 [ Sat Dec 18, 2010 7:01 am ] |
| Post subject: | |
get it shaved bigger valves 1.70/1.44 ,port , stonger springs ...run it.... build other head for turbo keep on roddin' |
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