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1989 K5 Blazer Cam Supporting Mods

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Old 10-10-2018, 08:28 AM
cmz
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Default 1989 K5 Blazer Cam Supporting Mods

I purchased a Cam for my 5.7L 350SB Blazer from a buddy, came with the lifter kit. I need to know how to determine what Pushrods and valve springs to purchase.

This is my first build, and could use any tips possible, especially if I missed any supporting mods for a Comp Cam lifter set. Thanks in advance.
 
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Old 10-11-2018, 01:59 PM
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Originally Posted by cmz View Post
I purchased a Cam for my 5.7L 350SB Blazer from a buddy, came with the lifter kit. I need to know how to determine what Pushrods and valve springs to purchase.

This is my first build, and could use any tips possible, especially if I missed any supporting mods for a Comp Cam lifter set. Thanks in advance.
Tell me exactly what it is that you bought from him and I will help you. Is this going into a stock 1989 K5 Blazer?

 
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Old 10-13-2018, 09:23 AM
cmz
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Originally Posted by LesMyer View Post
Tell me exactly what it is that you bought from him and I will help you. Is this going into a stock 1989 K5 Blazer?
I purchased the Comp Cams 270H. I'm not near the cam now, bit I can give specifics later today if this doesn't help enough .Thanks
 
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Old 10-14-2018, 12:26 PM
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Factory fuel injection/pcm or a carb? I'm familiar with the 270H
 
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Old 10-14-2018, 05:57 PM
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Originally Posted by LesMyer View Post
Factory fuel injection/pcm or a carb? I'm familiar with the 270H
Badge says fuel injected, and I know it has a carb .My first vehicle older than a 2005.
 
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Old 10-15-2018, 07:48 AM
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OK - lets figure out exactly what you have. Need number on pad on block at front of passenger side head. This should be right behind the alternator and is visible from above. Then pull the passenger valve cover off and read the numbers cast into the metal. Finally take a photo of the top side of your engine and post it. This is the only way to know if this cam is appropriate for your engine without further mods. Comp 270H is an old-school single pattern cam of moderate duration/lift with a 110°LCA and 106° intake centerline. Decent street cam in it's day with a little lope in the idle, and it's appropriately sized for a 350 on the street - but it's not going to play well with fuel injection or with poor heads/stock intake/stock exhaust.

Of most importance is the ID of the heads. If it has original swirl port TBI heads on it (such as casting code 193 suffix), a Comp 270H is completely inappropriate as these heads have horrible performance and will give up by the RPM where the cam should start working. These heads have center bolt valve covers.

Here, read this and pay particular attention to where they speak about the RPM capability of these heads.
https://www.hotrod.com/articles/hrdp...s-short-block/

Also, I'm assuming this is a brand new cam and lifters. You don't switch used flat tappet cams/lifters in different blocks - it just doesn't work out as flat cam/lifters develop a wear pattern specific to a engine block and will not live long in another engine.

If you want to build power and are lucky, the entire engine will have been replaced with a 1970's era 350. If you are very very lucky the entire engine will have been replaced with a later Vortec 350 and a carb.



 

Last edited by LesMyer; 10-15-2018 at 09:02 AM.
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