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#1
05-04-2004, 10:27 AM
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455 bored .030, standard .030 trw pistons. Any ideas on max lift, with these pistons?
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#2
05-04-2004, 10:27 AM
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455 bored .030, standard .030 trw pistons. Any ideas on max lift, with these pistons?
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#3
05-04-2004, 12:01 PM
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I was running .570/.585 something gross valve lift with 1.65 rockers which would put it in the .620-.630(???) in a non decked 455 and still had well over an 1/8" clearance. My old TRW slugs and stock rods were also .030 in the hole.
Just changed to SRP pistons and H-beams rods that are basically at 0 deck. and still had plenty of clearance.
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74 GTO Bracket/Street car and another 74 for the wifey to race with! 70 GTO 400, 4 spd, #'s matching and a little to nice for me to own. Friendship is like peeing your pants..everyone can see it but only you can feel the warmth! |
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#4
05-04-2004, 12:45 PM
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Don't forget that V-P clearance is also dependent on the duration of the cam. The larger the duration the less the V-P clearance.
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#5
05-04-2004, 04:07 PM
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Also dont forget different heads have different chamber depths. You have to factor that in.
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#6
05-04-2004, 04:13 PM
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255/265 duration cam at .050 on 106 c/l
with .594 intake and .618 gross lift, I had about .140 on the exhaust. This was with a TRW 2262 piston. Tom V.
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"Engineers do stuff for reasons" Tom Vaught Despite small distractions, there are those who will go Forward, Learning, Sharing Knowledge, Doing what they can to help others move forward. |
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#7
05-04-2004, 05:23 PM
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Heads makes a big difference as there can be 0.200 difference between a RAIV and a 6X-8 head.Deck height of the block also factors in.
Duration is the biggest factor and 8-12 degrees either side of TDC is the tighest areas. On my RAIVs a zero deck block and 2262s a 255/259 @ 0.050 solid was close but OK a 274 @ 0.050 was way too tight. You can add close to 0.050 clearance by blending the valve pocket out to the flat top in the middle of the "eyebrows". That ridge is where it hits.
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Skip Fix 1978 Trans Am original owner 10.99 @ 124 pump gas 455 E heads, NO Bird ever! 1981 Black SE Trans Am stockish 6X 400ci, turbo 301 on a stand 1965 GTO 4 barrel 3 speed project 2004 GTO Pulse Red stock motor computer tune [email protected] 1964 Impala SS 409/470ci 600 HP stroker project 1979 Camaro IAII Edelbrock head 500" 695 HP 10.33@132 3595lbs 1964 Corvette Coupe 327 4 speed |
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#8
05-04-2004, 08:51 PM
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My wife's car is a 455 .030 trw flat top motor with a Lunati 645 lift roller and 271-281 duration at .050. It has 62 d port heads on it.
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#9
05-05-2004, 04:26 AM
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thank you everyone for your responses.
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#10
05-05-2004, 07:54 PM
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I am running 87cc edelbrock heads with a gross valve lift of .633 .655 with trw rorged pistons and plenty of clearence, also revving the piss out of it.
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#11
05-09-2004, 08:23 PM
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actually, overlap is the determining factor, not lift, nor duration. i.e. tightening up the lobe separation will reduce piston to valve clearance, all else being equal.
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#12
05-10-2004, 01:55 PM
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On my solid cam motor, I had TRW's -.012" in the hole w/ 72 cc E heads, .600" gross lift (.580" net), .039" gasket, 263/271, 108 LS (102 IC) and it had a mile.
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