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73-87 Chevy _ GMC Trucks => Performance => Topic started by: 87GMC2WD on September 26, 2007, 04:07:31 pm
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hey guys,
i have a 1987 Sierra 2wd with 350 TBI and a 700R4. i know a guy who is selling a set of 660 cfm heads. i was also thinking about doing a cam. But im not queit sure on what cam i should use, im just looking for obviously more performance and possibly a "rougher" idle. Just wondering if those size heads would work ok and if anyone has any ideas about a cam. im only 17 and im just starting to get into the motor world. i know a decent amount about motors, but nothing too specifc. so a few pointers would be appreciated.
Thanks, Kyle
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What exactly did he mean by 660cfm? Is that how much he said they flowed? Maybe he meant 260cfm. Or maybe he meant that they were set up for a cam with 660 lift. If you get more info, I'm sure the guys on here could help you figure something out. I'm not sure about what cam to pick. I only have experience with GenIII engines. Good luck man.
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You are going to be slightly restricted on what cam you can use and keep the TBI. Getting a rougher or lumpy cam doesn't go well with EFI.
The heads need to be the 87-95 vortec heads with the vertical center holes.
Question is, how much tuning are you willing to get done or learn to make anything larger than factory and the factory computer work together? You can just dump a hot cam and heads in there and think the computer will take care of it, you need a plan. Since you are talking about a factory 350, I would start with a max 5500 RPM limit especially if you are going to daily drive it.
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maybe he was wrong about the cfm, but he said that they have a 660 chamber. so i guess that wouldnt be measured in cfm. and putting a cam in it will mess with the computer? how much is it to tune that? im just looking for a little bit more performace, nothing too crazy.
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chamber sizes are measured in cc's, like 76cc, 64cc, 54cc etc.
Putting anything to dramatic as far as cams go will require a new chip to be burned. I haven't check on the price, but generally they are about $100 for the old style if you need a guess.
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Ask him for the casting numbers off of the heads and then go to www.mortec.com to see what exactly they are. That will tell you combustion chamber size and runner size. It will tell you basically what year the heads were for etc. great site.
As for the cam, it all depends on what else you plan to do to your engine, trans, rearend gears, exhaust etc. So, once you figure out what you're going to do about heads, re-post. There are plenty of people on this site with info and experience. It's also a great idea to contact some of the cam companies tech lines. They can point you in the right direction. A rough idle sounds cool but is totally useless if you don't have the rest of the drivetrain to match.
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i have an 87 shortbed, and trust me..the FIRST thing you want to do is....save your money for a 96-2002 350 becaust the head on these trust really dont make ANY power after about 3000 rpm.
you can go with a decent cam..comp cam computer compatable cam. if you dont want a new chip then stick with a cam with lift under 450". im currently awaiting a pay check to buy a 300 hp vortec motor that is only 1300 with a warranty.
my truck is about 3900 lbs. i have full dual exhaust. k&n intake, custom chip from www.tbichips.com a holley aftermarket tbi, flex fan, racing radiator, strip/street stage 2 shift kit, corvette servo and the stock 3.08 one wheel wonder and im running mid 15's and the fastest being a 15.5 and hoping to be in the low 15's this weekend with tracton bars and 2600 stall. good luck
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the heads you have now are fine if you want a cheap upgrade and most bang for your buck buy some true roller rockers. Than if down the road you want more you haven't wasted any money you can put those rollers on you new motor. Second rough idle with tbi not good, don't even try going there unless you want to put a carb on and spend a lot of money.
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Do you know this post is a year old?
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how did that chip work from the website? i was looking at the hypertech one but idk if it will do anything