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97 Z71/Vortec Build

 
jokerZ71
I love my Chevy Chevette!
Posts: 22
Joined: 05/13
Posted: 05/05/13 06:49 AM

Hey everybody.I'm rebuilding the original motor I pulled @ 250K in Z.It wuz runnin strong & quiet,but,very low oil pressure.The Goodwrench crate I replaced it with is @ 280K now & havin the same problem.Truck is my DD.I drive 100 miles a day to work.I also pull 2 or r times a year @ local truckpulls,do some pretty serious muddin,pull my horses,& 4 wheelers.Waitin for the machine shop's verdict on to bore or not.My measurements say no,but,we'll see.Plans so far are to deck block to .015 & headgasket thickness of .028 to tighten up over the original .053 quench.Using 12 cc D pistons,& #14097395 cam.(ramjet/ht383 cam),spring upgrade,&1.52 roller tip rockers,& a PCM tune to bring it all in.Does anybody see any problems or redflags on this combo?I'll also be running mid length header w/ Y pipe into a 3" single TP. Davis Vortec Firepower ignition system.Hoping for about 320 FWHP.  
97 Z71 extended cab,5.7,4L60E,285/75-16,American Outlaw Buckshot Wheels.528,000 miles.

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redneckjoe69
I mow my lawn and find Chevys
Posts: 2337
Joined: 03/10
Posted: 05/05/13 12:34 PM

350, correct?     what heads?  do you have the casting number of the heads?    i dont see problems, but some flat-top pistons could be a good choice for more power?  

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jokerZ71
I love my Chevy Chevette!
Posts: 22
Joined: 05/13
Posted: 05/05/13 01:05 PM

Heads are stock 906 heads.Flat tops are puttin my compression up in the 10:1 range unless I use the 1.540 CH flat tops which will kill my quench.This is the original motor that came in the truck.I bought it new in 97.Really amazed @ how little wear there is on everything @ 250,000 miles.The stock compression is 9.4:1 with the OEM dish pistons & .053 quench.I figure I could still bump it up just a bit with this cam,pistons,quench,& a PCM tune.I'm keepin the PCM & EFI.Due to the miles I drive everyday'tryin to stay low on octane requirements.  
97 Z71 extended cab,5.7,4L60E,285/75-16,American Outlaw Buckshot Wheels.528,000 miles.

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jokerZ71
I love my Chevy Chevette!
Posts: 22
Joined: 05/13
Posted: 05/05/13 01:17 PM

My figuring withis combo has me @ a DCR of 7.8:1 & SCR of 9.6:1.The only flat tops I could find with a 1.56 CH were bout 7 cc.I needed a minimum of 10 to 12 cc to keep DCR in ck with 87 or 89 octane.Gas these dayz sux !!!  
97 Z71 extended cab,5.7,4L60E,285/75-16,American Outlaw Buckshot Wheels.528,000 miles.

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jokerZ71
I love my Chevy Chevette!
Posts: 22
Joined: 05/13
Posted: 05/05/13 01:30 PM

Trying to leave a lil room for error also cuz I've read these heads could cc as low as 62,or,as high as 66 instead of the 64 they should be.I'm worried if I get compression too high,the PCM could detect some detonation & start pullin timing out which will defeat my purpose.Hopefully a good tune will take care of that.Fingers crossed !!! LOL.  
97 Z71 extended cab,5.7,4L60E,285/75-16,American Outlaw Buckshot Wheels.528,000 miles.

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jokerZ71
I love my Chevy Chevette!
Posts: 22
Joined: 05/13
Posted: 05/08/13 01:54 PM

Summit has a set of hyper flat tops w/ 4 VR & 1.56 compression height.Advertised compression w/ 64 cc heads is 9.6:1. Would these be ok to run w/o havin to use 91 octane.Has anybody used a set of these in a Vortec 5.7 ? I would much rather use the flat top vs the D dish.  
97 Z71 extended cab,5.7,4L60E,285/75-16,American Outlaw Buckshot Wheels.528,000 miles.

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redneckjoe69
I mow my lawn and find Chevys
Posts: 2337
Joined: 03/10
Posted: 05/08/13 02:24 PM

im just running an old school 350 with flat-tops and 64cc heads, yup, gotta run premium.   but im running 37 degrees total timing on a carb and non-computer controlled ignition.  
  id go with the flat-tops for power,...thats just me.   JMO.    your computer/knock sensor will back the timing down if it hears a problem.   get an adjustable fuel pressure regulater and crank it up for the fuel injection.

 is this the cam in question?
http://paceperformance.com/i-6255412-14097395-hydraulic-roller-camshaft-ht383-crate-ramjet-350.html

  heres an article on cranking up fuel pressure.  
http://www.thirdgen.org/optimal-fuel-pressure

   what kinda FI are you running?   TBI?  

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jokerZ71
I love my Chevy Chevette!
Posts: 22
Joined: 05/13
Posted: 05/08/13 02:45 PM

I'm running the stock vortec EFI,but,I do have the upgraded version.Yes that is the cam I'm plannin on using.I had planned to do a 383,but,my youngest got in a lil trouble,so,the bail bondsman & court wound up with my motor money.LOL.  
97 Z71 extended cab,5.7,4L60E,285/75-16,American Outlaw Buckshot Wheels.528,000 miles.

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68scott385
I mow my lawn and find Chevys
Posts: 1994
Joined: 10/09
Posted: 05/08/13 03:03 PM

What do the stock piston tops look like? Can you post a pic of one.

IIRC the Vortecs from that era came from the factory with an advertised 9:1 compression.

From the factory, the Vortec FI system needs at least 55psi to run.  
68scott385 68scott385 68scott385

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jokerZ71
I love my Chevy Chevette!
Posts: 22
Joined: 05/13
Posted: 05/08/13 03:51 PM

I don't have a pic of them.They have the dish in the center with approx 7/16" wide quench pad ??? Around the entire top.  
97 Z71 extended cab,5.7,4L60E,285/75-16,American Outlaw Buckshot Wheels.528,000 miles.

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jokerZ71
I love my Chevy Chevette!
Posts: 22
Joined: 05/13
Posted: 05/08/13 03:56 PM

A Stock compression is advertised @ 9.4:1 with the dished piston & from my measurements,a .032 headgasket.  
97 Z71 extended cab,5.7,4L60E,285/75-16,American Outlaw Buckshot Wheels.528,000 miles.

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68scott385
I mow my lawn and find Chevys
Posts: 1994
Joined: 10/09
Posted: 05/08/13 04:00 PM

Does it look like this?

Stockpiston  
68scott385 68scott385 68scott385

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jokerZ71
I love my Chevy Chevette!
Posts: 22
Joined: 05/13
Posted: 05/08/13 05:24 PM

pretty much.mine have a slight crosslike ridge in the center.You can see it,but,just barely feel it with your finger.  
97 Z71 extended cab,5.7,4L60E,285/75-16,American Outlaw Buckshot Wheels.528,000 miles.

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jokerZ71
I love my Chevy Chevette!
Posts: 22
Joined: 05/13
Posted: 05/08/13 05:40 PM

I have a pic now,but,I don't know how to post it.  
97 Z71 extended cab,5.7,4L60E,285/75-16,American Outlaw Buckshot Wheels.528,000 miles.

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jokerZ71
I love my Chevy Chevette!
Posts: 22
Joined: 05/13
Posted: 05/08/13 06:12 PM

it's kinda hard to tell from the pic,but,I think the outer raised area is wider on my piston creating a smaller dished area.  
97 Z71 extended cab,5.7,4L60E,285/75-16,American Outlaw Buckshot Wheels.528,000 miles.

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