73-87chevytrucks.com
73-87 Chevy _ GMC Trucks => Performance => Topic started by: trink2030 on September 13, 2010, 08:02:01 PM
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Hello all, been lurking around here for a few weeks and came up with a lot of good information, but need more specific information.
I have a 1985 GMC dually.
4:10 gears
stock 454
I believe, a muncie 4 speed
I have a chevy friend that tells me that I can get a lot more torque by only installing a cam, but after reading here a while I find that hard to believe.
While the truck has a lot of power stock, there is still a lag when shifting between first and second when carrying a heavy load. I would like to fill that gap a little.
What do you guys think of just installing a cam to the truck to add more low end? I'm not on a budget, but am trying to keep in mind that this isn't a necessity.
I like the idea of replacing my 2 barrel with something larger or moving to sec vac.
Any thoughts?
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The 4 speed is a Granny Low, so the gap between 1st and 2nd will always be there.
You are going to have peanut port heads which are fine for up to about 5200rpms, but that is about it. I wouldn't put to aggressive of a cam with those heads.
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Thanks for the reply. I'm not opposed to swapping for a 400, the wife wants me to do that anyway as that clutch is a little heavy for her. Sounds like to me you wouldn't put a cam in it. Do you have any thoughts if it were a 400 instead of the 4 speed?
Thanks
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IMO you would probably like the TH400. I have that trans in my 85 behind a 454 but I have the 3.21 gear. I like the clutch though, my wife can't and won't learn how to drive a standard shift so that keeps her out of my baby unless she is a passenger... 8)
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Been reading a little more, I think I'm going with the 400....seems to be an easy weekend project and I've never had a truck project supported by the wife, so that's that.
So now, with the truck with a 400, what power options do I have?
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You are still limited by the heads.
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I like the idea of replacing my 2 barrel with something larger or moving to sec vac.
Any thoughts?
I thought a 454 would have a 4 barrel on it from the factory.
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The peanut port heads are great on a truck like yours. The have excellent port velocity which means excellent cylinder filling at low rpms. This is great for monster low end torque and pulling power. Chevelle guys are using the peanut port heads with a small Voodoo flat tappet cam (601-602 models), peanut port intake and stock quadrajet and running fast all below 5,500 rpms. Of course they do not have a granny low 4 speed which is your real "go fast" killer.
On mine, I bumped the initial timing up from 4* to 12* and opened the exhaust and mine woke up quite a bit.
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got a nice 400 today....can't wait for the weekend.
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I need a nudge kaos, are the heads something that are going to need to be replaced or just machined?
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They are fine for up to about 5000 rpms, and will do fine for most street driving, but if you are building something with a 2500-6000 or higher rpm range, I would switch to real oval ports. I would NOT use square ports.
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I'm staying below 5000rpm. So by what I read here there's nothing I can do to pep up my 454?!?! There's either a lack of know-how or a lack of interest in here to help out...either way I'll find somewhere else to find information.
I'm not attacking anyone, just trying to point out a lack of something here.
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I'm staying below 5000rpm. So by what I read here there's nothing I can do to pep up my 454?!?! There's either a lack of know-how or a lack of interest in here to help out...either way I'll find somewhere else to find information.
I'm not attacking anyone, just trying to point out a lack of something here.
Really no way to talk being your 6th. post. You won't find a better forum out there if you give them a chance. I think you should put the TH400 in and see how you like it. It will feel a bunch better I promise. With your gearing it should be very quick off the line. More info is needed as to what you are looking to do with the truck. You probably only get 9 mpg with it so anything you do won't make it better. Do you need to pass any emission tests? Your truck probably has factory dual exhaust and no cats from the factory but has dual air pumps. Do you want to run it down the highway without the engine screaming? Lots to think about before you make the above statement.
My 85 in my signature which I drive like a grandma, most of the time, will break the tires loose in third gear if I stand on it just taking it easy. I am in 3rd gear by 25 mph and it is bone stock, everything original under the hood, Carb never touched except a choke pull-off, original factory exhaust and 134K on the clock. That is with a 3.21 gear out back.
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I see many good pieces of advice...
I would get rid of the 2bl carb and intake.
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I would get rid of the 2bl carb and intake.
I posted this before but has anyone seen a 454 with a factory 2 barrel on it?
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Apparently the OP has
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I'm staying below 5000rpm. So by what I read here there's nothing I can do to pep up my 454?!?! There's either a lack of know-how or a lack of interest in here to help out...either way I'll find somewhere else to find information.
I'm not attacking anyone, just trying to point out a lack of something here.
I don't know alot about the big block's but you are overlooking alot of simple things that I think apply to any internal combustion engine. Ditch all the unnecessary equipment that you don't need for emissions, tune it up and upgrade your ignition system, exhaust, and fuel delivery. I haven't heard of a 2-barrel carb on a big block either, but there are a bunch of screamin 454's that guys on this site have that are running 4-barrels. I would look into that.
So by what you read here you could follow the path where you end up with easily a 500+ hp 454 by taking suggestions about swapping heads, cam, intake, etc. or leave us all wondering if you are asking about a motor full of vacuum leaks with a pinched fuel line wondering why you don't have more power out of your 454. Welcome to the site by the way. 8)
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That's good advice...thanks for not taking my post the wrong way although a little harsh now that I reread it, sometimes online doesn't catch the 'essence' of a message the way it should.
The 400 is in and sieg was right, it feels a LOT better. I was wrong about the 2bbl, it's a 4 that's my mistake.
The truck runs great, a real clean idle and rev....no wierd sounds or misses throughout. I am going to start removing all of the junk that's not needed, maybe I'll be able to 'see' the motor once all of that is off. I'm going to have to start researching what is involved in removing all of the emissions, a procedure perhaps on the proper way to attack it without issues.
in reply to zieg, I don't care about mpg down to 5-6 or so.
Ignition is a good and relatively cheap idea, I'll knock that out second.
Thanks for the help
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Want more power and most important torque.
Yes,change the cam to something like a comp cam Extreme energy 262H or a 268H.Get the matching valve springs too.
A nice dual plane intake like the Edelbrock performer or even the performer RPM(works well with 268H cam).Even with the stock penut port heads.You could reach 400HP and close to 500lb-ft of torque with ease. 1 3/4" headers and 2.5" exhaust system will wake the old truck for sure.
The stock low compression hurts it a bit though.....If you decide to do a rebuit,try to bring the compression around 9.25-9.5 to 1. With the same setup,you could see 30-50HP more,and may reach close to 550 lb-ft of torque.