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#1
08-26-2012, 08:04 PM
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455 with 62's... Thoughts
Got a stock 70 455... Getting a set of 62's for free... Wanting to run RAiii cam as well.. From what I've read I've heard good and bad points about this combo. Not really wanting to change pistons or get into anything major...anyone running this combo or have in the past?
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70 Judge Ram III M21 3:90 71 Lemans sport 4spd (endura optioned) 71 Lemans sport Lucerene Blue |
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#2
08-26-2012, 08:09 PM
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Don't do it! Buying race fuel will get old fast!
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1966 GTO 1969 Lemans Convertible- F.A.S.T. legal family cruiser. 12.59 on G70-14 Polyglas tires. 1.78 60' 1969 Bonneville Safari- cross country family cruiser. . 1979 Trans Am 400, 4-speed, 4 wheel disc. View from the drivers seat racing down Atco Raceway- http://www.youtube.com/watch?v=GhYDMdOEC7A Ride along in the other lane-http://www.youtube.com/watch?v=mIzgpLtF_uw |
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#3
08-26-2012, 08:18 PM
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Altitude makes a difference. Lot's of 10.5:1-ish cars running around the Colorado high country on 89 octain pump gas.
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Cum Catapultae Proscriptae Erunt Tum Soli Proscripti Catapultas Habebunt. 
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#4
08-26-2012, 08:25 PM
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do have just the block or a complete 455? what heads are on the 455 right now?
i would sell the 62's(200-250 complete)and buy some 1971#96or some small chamber 4X/6X. you could run the 62, but no reason to. there are other heads that you could run and make as much or more power without the problems with running compression right on the edge.
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FREEDOM ISN'T FREE BUT WORTH FIGHTING FOR |
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#5
08-27-2012, 09:45 AM
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I did a .030 455 w/ 48 heads, small cam & a q-jet 4 speed. You could tell when the race-pump gas mix got weak right away. It was a torque monster, that's when cam 2 was reasonable priced-25 yrs ago. John
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#6
08-27-2012, 12:54 PM
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Quote:
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72 lemans,455 e-head, UD 255/263 solid flat,3.73 gears,,,10" 4400 converter,, 6.68 at 101.8 mph,,1.44 60 ft.2007 (cam 271/278 roller)9"CC.4.11gear 6.41 at 106.32 mph 1.42 60 ft.(2009) SOLD,SOLD 1970 GTO 455 4 speed #matching,, 3.31 posi.Stock manifolds. # 64 heads.A factory mint tuquoise ,69' judge stripe car. 8.64 @ 87.3 mph on slippery street tires.Bad 2.25 60ft.Owned since 86' Last edited by scott70; 08-27-2012 at 01:01 PM. |
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#7
08-27-2012, 02:45 PM
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Won't work, horrible choice unless you plan to run high grade racing fuel non stop.
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#8
08-27-2012, 02:57 PM
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Dont do it. Tried it once and broke a crank. Pinged really bad.
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http://www.machdevelopment.com/album...775/527566.htm |
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#9
08-27-2012, 07:04 PM
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Okay thanks guys. My dad is giving me a set for my birthday so I have other options here.. Set of 6x-4's, 6x-8's, he doesn't want to let go of any 96's.. The 455 is complete in the car with 15 heads. I am wanting to run headers, new RAiii cam.. Just wanting a little more out of this engine.
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70 Judge Ram III M21 3:90 71 Lemans sport 4spd (endura optioned) 71 Lemans sport Lucerene Blue |
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#10
08-27-2012, 07:42 PM
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Try this out for the best 6X which in my book is the only way to fly with a 455.
http://www.428gto.com/page5.htm |
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#11
08-28-2012, 02:24 AM
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Its Doable!
Yes, running 62s on a 455 gets you alot of compression, but with large valves and screw-in studs and guide plates is a GOOD choice! however, a couple of items were overlooked in the previous posts. First, you said you will be running a Ram Air 3 cam, I will go on the assumption that your cam is the 744 or "H" grind, a good choice, for you have in that cam 76 degrees of overlap which effectively lowers the dynamic cranking pressure of the engine. A similar example is the 041 cams 87 degree overlap which in reality drops the cranking pressure down in a ram air 4 engine from 10.75 compresion down to 6.6 (this according to an article I read authored by H.O. Racing Specialities of Lawndale, Ca some years ago). Also, I just checked H.O.s "Pontiac Heavy-Duty parts & specs" and checked the computed static compression ratio chart for 455s with a 75cc chamber head on page 31(cast 62 heads read out at 75ccs according to to this pub). The chart indicates with this block/head combo a compression ratio of 10.72-std bore or 11.00-at 60 over will occur-not too bad-this compression will make some good horsepower!-throttle response should be very good. The second overlooked item is ign advance-you don't have to have it cranked to the max advance possible or have it all in by 2000rpm. A little restraint in this area may yield a bodacious engine. Also using a manual trans and some stiff gears will help by ensuring the engine is not saddled with a low rpm lugging situation- I would use a wide box and 3:90s-you'd be wild in the streets with that combo!! Just a recommendation from playing with pontiacs since 1972-Respectfully, Rick K.
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#12
08-28-2012, 10:33 PM
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i'll vote for the 15's, just convert to screw in studs. the 87ish cc will make good compression, that's still pump gas friendly. it should run well with a 744 but, imo, it's begging for a 041
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