1986Z28OWNER

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I recently built a Vortec headed 383 for my 86 IROC, last saturday we finally got around to putting it on the dyno. The Specs are as follows:

"880" roller block, Scat crank, Compstar rods, wiseco forged pistons, 10.2:1 CR, custom hyd roller cam (.563"/.544", 224/229 duration @ 0.050", 110 LSA, installed on a 108 intake centerline) 906 vortec heads, CHE bronze valve guides installed to solve the retainer to seal clearance issue, valve sizes were opened up to 2.02"/1.60", Bowls were blended to accomodate the new larger valves, spring pockets were cut to fit a beehive valve spring, machined them for screw in studs and guideplates. No other porting was done to the intake ports, the exhaust we raised the roof of the port 0.075" and opened up around the guide. The intake was a edelbrock performer RPM, with AED 750HO carb.

Here are some shots of building/machining the engine...

Boring it the cylinders



Surfacing the block



Torque plate bolted on, preparing to hone the cylinders



Honed!



Weighing parts for the balance





Scat crank



Balancing the crank





Checking pin bore clearances.

1986Z28OWNER

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Block all washed up





Block painted w/ cam bearings and plugs installed.



Checking bearing clearances



Crank and cam in.



Degreeing the cam, I advanced it 2 degrees.



Checking my rod bearing clearance



Gapping piston rings





Assembling the rods and pistons

1986Z28OWNER

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All together and in the engine...





Shortblock almost done.



Checking rotating clearance on the pan, had to notch it for the lokar dipstick. Thats it.





Bolted up



Porting the exhaust ports



Valve job and blending done to the bowls



Crower Enduro stainless bodied 1.6 ratio 7/16" stud rockers



Isky adjustable guideplate to get the rocker tips to sit properly

1986Z28OWNER

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I was originally goign to run a Comp dual spring, witha crower titanium retainer but I wanted to lighten up the valve train so I switched to a beehive witha steel retainer. Big weight savings





Porting all finished up



cc'ing the chambers



Spring pockets machined to fit a ID style of locator



A bunch of material ground out of the pushrod area



Surfacing the heads



Porting the intake





Heads surfaced

1986Z28OWNER

iTrader: (1)

Stud bosses milled .400"



Lapped the valves



Figured out my pushrod lengths



Did a mock assembly to check PTV etc... had .140"+ PTV on both the intake and exhaust, brow clearance was good aswell.





Heads fully assembled



Bolted on



Guideplates fit and studs torqued down where I want them



Manton 5/16" .118" wall 7.300" pushrods

1986Z28OWNER

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Rockers installed



We lube the pushrod and valve tips with this



Filled with Joe gibbs breakin oil



Checking port alignment



Intake bolted up and sealed, primed it, had 60psi oil pressure, had oil to all 16 rocker in under 20 seconds.



Pretty much ready for the dyno.

1986Z28OWNER

iTrader: (1)

Bolted it up to the dyno friday night, my hooker supercomp headers wouldnt fit so I bolted up a set of out 1 3/4" dyno headers.

Started the jetting out at 72's in all 4 corners with 4.5" power valves, First pull it made 451HP, and 472 ft-lbs of tq.

Took two jet sizes out of it and made another pull, 455 HP and 475 ft-lb's of tq.

BSFC was telling us the fuel curve was where is need to be, So I gave it another 2 degrees advance (34-36) which picked up the HP a bit

We figured it wanted more plenum volume so we tried a 1" open carb spacer which woke it up alot. W/ 36 degrees total timing, 70's all around it made 466hp, and 486 ft lb's of tq.

We had a bit to much oil pressure, so we drained the breakin oil, cut open the oil filter, which was clean, and filled it up with Joe Gibbs 10w30 synthetic hot rod oil. We also blended the 90 degree edge where the choke horn was milled off and jetted the primaries up 1 size to a 71. Opened up the high speed air bleeds 0.005" as it was a little fat in the top end. This pull brought us to out final numbers 474HP @ 5500RPM, and 493 ft-lbs of tq @ 4800RPM. It made over 420 ft lbs of tq at 3000 RPM and carried it to 6000RPM. Overall I am very happy with the results considering its a GM head casting with dual plane intake.

Here is a video of the second to last pull

http://www.youtube.com/watch?v=ni0xCy9bmTM

conlinj

iTrader: (3)

Nice results, can't wait to see some ET's out of it. Also it gives me some ideas for my old vortecs that are sitting around. Hopefully my AFR vortecs make as much power as yours did.

-Jim

Cosmik Debris

You don't have any more pictures do you? :-) Nice job.

1986Z28OWNER

iTrader: (1)

Yah, look at my build thread haha.

L695speed

I just found this thread, sounds like you did something very similar to what I had in mind. Guess I won't be worrying about the power LOL! I was hoping for 425 or so. But it seems like I'll getting what I want and then some. Where is your build thread so I'm not digging through all the threads looking for yours.

UnstableAviator

Once you get it installed, it sure would be interesting to see a chassis dyno result! I always see engine dyno numbers, or chassis dyno numbers, but rarely both.

I enjoyed the pics, real nice build and that's gonna be one torque monster engine. Good luck with traction on the street.

Atilla the Fun

Good results.

1986Z28OWNER

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There is a link to it in my sig.