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Old 06-01-2011, 11:46 PM   #1
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Default 1974 Grandville 455 Performance?

hello, im new to this forum and im in the process of fixing up an old 1974 grandville with the 455. i was wondering what i can do to unleash some more power or any mods that respond well with the 455? also what smog stuff can i remove to wake it up. i was thinking about a cam and intake manifold and maybe a different carb, although it does have the factory holley on it. any imput at all would be great thanks!
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Old 06-01-2011, 11:56 PM   #2
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It all depends on how far you want to go you can go cam/carb/headers aluminum intake n call it good
Or you can go cam carb intake headers rockers .30 bore hi performance coil and ignition controller box ect ect
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Old 06-01-2011, 11:59 PM   #3
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increasing the bore isnt really an option and do you think there will be a noticable seat-of-pants difference with the mods i stated? also will the ignition really make that much of a difference? forgive my lack of knowlage about this im 17 and this car has been sitting in my garage for 20 years and i want to make it a sleeper i guess you could say. just trying to learn as much as i can by diving into this project but all the little advice helps a ton
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Old 06-02-2011, 12:02 AM   #4
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if you go with a good cam an aluminum intake and a newer carb as long as you get a good exhaust going with i think you may notice it.But another idea if you have a spare set of heads laying around you can practice porting and polishing them just for giggles and if your good enough do yours
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Old 06-02-2011, 12:05 AM   #5
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yea i was thinking about porting and polishing them while i had the intake stuff apart might as well take that apart to and my dad did it in his blazer and a k10 he had so he should be able to help me out. also ive heard alot of 70s cars have smog stuff that corks them up is that true and if so what is it so i can get rid of it since emissions are no longer a probolem for this car
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Old 06-02-2011, 12:12 AM   #6
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Well there may be a ''smog pump'' and a bunch of smog crap on the manifolds and also an egr..that could all be removed
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Old 06-02-2011, 12:15 AM   #7
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i hear alot of people talking about "uncorking" these engines. i come from the dirtbike world and that generally means a more free flowing exhaust and intake work. i guess people are saying around 400hp and around 500 ft pounds when its uncorked? that sounds really hopeful to me
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Old 06-02-2011, 12:25 AM   #8
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Start with your exhaust, headers, then a cam, so head work will help as well. Get the engine to breath as easy as possible. A larger carb, like a nice 4 barrel. SGP358 does a lot of classics work, he may be able to give some good advice.
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Old 06-02-2011, 07:47 AM   #9
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if you want over 400hp your likely going to have to get aftermarket heads too, low compression and 70'* heads dont really make much power. i dont know the specs of your engine normally i play with SBC'* but i bet you could find some heads that increase your compression some add cam, carb, intake, headers, etc,
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Old 06-02-2011, 11:37 PM   #10
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Does it have points or HEI? If it has points, get a better system and a hotter coil 1st.

1974 was NOT a good year for performance! These cars were totally detuned for emission purposes. You car should have a factory Rochester Quadrajet carb.

Does it have 4X or 6X heads? If so, they should be OK. As was said before, beef up your ignition system 1st and install a dual exhaust system and see what happens.
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