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#1
08-02-2012, 08:51 PM
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Should I port my stock intake?
OK Gang here is the deal:
77 TA with AC, 455 with 4.25 Eagle crank, SRP +.035 Pistons, Eagle 6.80 rods. Heads done by SD Performance back in 2006. Flow sheet shows 245 at 600 lift. Cam is the old UD 231/239 around 500 lift on a 112. 1 3/4 Hedman headers, 2.5 duals with H pipe. Aftermarket ST-10 with the deep first gear with 3:23's out back. Q-Jet atop of a bone stock Edelbrock Performer. After reading Rocky Rotella's articles about how the performer sits 1/4 lower in the back, therby dropping the shaker and how Cliff Ruggles states the E-Performer is a restriction I'm going back to the stock 77 intake. My question is, is it worth having SD port it ? For 400 bucks and 3 horspower I wont do it. Is there more to be had with modifying it ??? Thanks in advance !!!
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http://www.highperformancepontiac.co...o_convertible/ |
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#2
08-02-2012, 09:08 PM
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What heads? I wouldn't put any time or money into a stock EGR intake only because they are ugly and heavy. I'd use a 234, 140 or 068 as they seem to be the most common I've seen from the 68-72 iron intakes.
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 ___________________________________ "Objects in mirror are closer than they appear" 
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#3
08-02-2012, 09:13 PM
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Quote:
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http://www.highperformancepontiac.co...o_convertible/ |
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#4
08-02-2012, 09:20 PM
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I had to make the same decision, kind of. It was easy for me after reading everything I could get my hands on. The guys that realy know what they are doing and have the time to do it can get realy good power out of good stock intake manifolds, with a lot of modification. Time equals money, and I have yet to see anyone that has done it offer to sell a highly modified stock intake for the price of a intake that is within 10 hp at near the same price. I'd rather spend 4 or 5 hours port matching a $240 intake than screwing up a good stock intake because I don't know what I'm doing.
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#5
08-02-2012, 09:48 PM
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No,harm in gasket-port/flange matching, right?
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#6
08-02-2012, 09:59 PM
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Does that thing have the 'D' shaped secondary holes? Since its a sleeper, some plenum mods ala Jim Hands book should be a stealthy improvement in addition to what H.I.S. posted.
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___________________________________ "Objects in mirror are closer than they appear"
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#7
08-02-2012, 10:05 PM
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1977 and later intakes have the D-shaped secondaries, they're not a performance hindrance.
I'd port match it and leave the rest alone. Even port matching won't add up to much if anything, but at least you can say that you did it.....  Professionally done plenum mods might buy you 10 to 15 HP on a 500 HP engine, but only you can decide if the investment is worth it. |
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#8
08-02-2012, 10:11 PM
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Quote:
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___________________________________ "Objects in mirror are closer than they appear"
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#9
08-02-2012, 11:02 PM
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I say just port match and blend it up a little. You can do that yourself.
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Tim Corcoran |
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#10
08-02-2012, 11:16 PM
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As humorous as a few horsepower may be, if you pick up a few here and a few there suddenly you have 30 more horsepower than the guy that thought all that stuff was just a waste of time.
Do it.
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 frittering and wasting the hours in an off hand way.... 1969 GTO, 455ci, 230/236 Pontiac Dude's "Butcher Special" Comp hyd roller cam with Crower HIPPO solid roller lifters, Q-jet, Edelbrock P4B-QJ, Doug's headers, ported 6X-8 (97cc) heads, TKO600, 3.73 geared Eaton Tru-Trac 8.5", hydroboost, rear disc brakes......and my greatest mechanical feat....a new heater core.
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#11
08-02-2012, 11:24 PM
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Quote:
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#12
08-03-2012, 12:02 AM
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I never have figured out how you can put a big slab of cast iron in the path of the secondaries and not screw things up. I remember reading the comments, but can't locate the thread at the moment. Was this on a mild 400 with the cam dropping off at 4,800 RPM, or was it on a 455 with SD ported heads, headers, and a 6,000 RPM power peak? One moment we are told we are loosing a substantial amount of horsepower by not having the secondary butterflies fully open, and then told we are not loosing any by blocking off a third of the secondary air path. Maybe it is so, but can someone explain how the manifold gets away with it?
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Mick Batson 1967 original owner Tyro Blue/black top 4-speed HO GTO with all the original parts stored safely away -- 1965 Catalina Safari Wagon. |
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#13
08-03-2012, 12:05 AM
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Rocky did an article in HPP where they flowed the intake and it did not loose any to earlier intakes. Many of the NHRA stockers are running deep 11s with them on a low compression motor-faster than alot of guys with Performer RPMs!
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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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#14
08-03-2012, 12:14 AM
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Pretty sure it has to do with a 'dead area' in the intake, the secondaries direct the airflow in such a way that the D-shaped opening doesn't affect performance.
As Skip said, some of the quickest NHRA stockers run the late restricted intake that matches the 6X heads on both 350 and 400 low-compression engine combos. |
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