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  #1 (permalink)  
Old 03-18-2007, 11:47 AM
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gmc syclone?

is the cylinder heads of a 90 91 92 gmc syclone the same chamber design as th 96 model 4.3 vortec head?
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Old 03-18-2007, 11:51 AM
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no. the VORTEC's are better
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Old 03-18-2007, 11:54 AM
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i didnt think they were, imagine the 96 vortec head with the turbo. if i ever get my hands on one to redo or restore in the future thats what im gonna use.
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Old 03-18-2007, 12:09 PM
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its a mod that those guys like to do. for those that can't afford nascar heads.
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Old 03-18-2007, 12:13 PM
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damm ,man. were you in that truck ? what happened ?

check out my photos, for something different.
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Old 03-18-2007, 12:27 PM
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Quote:
Originally Posted by Vortech 4.3
damm ,man. were you in that truck ? what happened ?

check out my photos, for something different.
i was running from the law, they clocked me 160+, after i lost them i turned off on my home road and didnt let off soon enough LOL so i slid off the road into a creek bed i remember 80mph but hwp recorded 65 from tire marks only thing was they were my front scooting sideways. 45 minutes later they show up and believe or not i never got fined one thing they said their radar wasnt set for that high or something couldnt tell if it were climbing or dropping speed. it happened 1:00 am i had it home before daylight and i never even went to the hospital, but i did go partailly blind in the left eye the next day. turns out the blow to my chest from the seatbelt caused a stroke. it was on state route 141 thats how i got the name. 9 days later i had another one bought and 9 months later i had it on the road
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Old 03-18-2007, 12:54 PM
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well, thats a story there .

and, thanx. i like my truck, maybe to much. but its about the only hobby i have.
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Old 03-18-2007, 12:58 PM
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aint nothin wrong with likin it too much, im on my 5th one
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Old 03-18-2007, 06:05 PM
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syclone

The later vortec heads will work but the syclone lower intake manifold has to be machined or the cylinder head manifold bolt holes need to be welded up and re drilled I have a set of those mid 90's vortec's for my 91 S-10 "syclone power'd sleeper" but will need to get this done when i get around to doing the swap.
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Old 03-18-2007, 06:07 PM
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i had forgot about the intake bolt pattern
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Old 03-20-2007, 03:36 PM
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stock syclone heads (LB4's) are a totally different chamber design than the 96+ (vortec) heads. The 96+ heads have a kidney bean shaped fast burn chamber.

1993-1995 non syclone/typhoon heads (L35's) are a direct bolt on head for the syclone and owners have reported measurable increases in power after installing them.

I run 1996+ heads on my syclone with a stock intake. In order to pull that off, I had to redrill the vortec heads for my syclone lower intake bolt pattern. Also, I added material to the lower intake the machined the welds and port match in order to seal the taller vortec head intake ports. I'll see if I can dig up some pics of this.
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Old 03-20-2007, 04:03 PM
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vortec head chambers




stock syclone intake





stock syclone intake welded up




The above pictures aren't mine. The vortecs can really use match porting. The below pictures are some match porting we did to mine over a year ago. You can clearly see where I redrilled the vortec heads for use with my syclone intake.
















Here's a pic of my engine bay with the vortec heads installed. You can't even tell unless you really know what to look for. I drive the truck almost every day.





Last edited by sy733; 03-20-2007 at 04:15 PM.
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Old 03-20-2007, 08:28 PM
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syclone?

Thanks for posting those pics of the heads and intake the casting numbers on my 4.3 vortec heads are 10235772 and they wer cast in 1996 I was gonna have them machined for 2.02 and 1.6 valves i have a spare lower syclone intake so i can start drilling and machining without taking the truck apart.How much power did you feel from doing the head swap to these over how the orig heads felt?
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Old 03-20-2007, 11:07 PM
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Quote:
Originally Posted by 12second6
Thanks for posting those pics of the heads and intake the casting numbers on my 4.3 vortec heads are 10235772 and they wer cast in 1996 I was gonna have them machined for 2.02 and 1.6 valves i have a spare lower syclone intake so i can start drilling and machining without taking the truck apart.How much power did you feel from doing the head swap to these over how the orig heads felt?

You're welcome. You have the correct heads if they're 772's. If I had to do this over again, I would have used a #2114 edelbrock bolt on lower intake and something like the following intake elbow rather than all the drilling, welding and machining of the syclone lower. http://www.intakeelbows.com/lt1_twin_52mm.htm people have reported very nice gains going this route. Some people have produced data that shows the syclone intake unevenly distributes air at really high horsepower and boost levels.

Just by swapping to vortecs, I was able to run a few more safe lbs. of boost and other syty people say they can run alot more timing by swapping to vortec heads. No other real notable differences for me because I had been running heavily ported L35 heads (93-95) before these lightly ported vortecs anyway.

Some people report 50hp increases on the dyno when going from the stock crappy syclone heads to vortecs. Regardless, the vortec heads offer great bang for the buck.

If you do decide to mod a syclone lower, keep in mind that it is very important to mock up the heads and lower intake with the thick intake gaskets you'll be using for the purpose of getting those holes suitably lined up. also, it appears the angle of the intake port surface vs. the port surface of the heads seemed to be about a degree or so off and caused me some sealing problems at the bottom of the ports at first. I haven't heard to much about that so maybe it was only me and another guy from canada that reported it.

I'm not trying to scare you away from using the syclone intake just offering another option before you go drill a perfectly good set of heads that you really worked on and spent $$ on.

I built my truck on a total budget and have had passengers tell me that the acceleration of it separated their body from their soul. But I don't exactly push the limits by running a max of only 20 psi boost and 19 or so degrees of timing so I don't see the unevenness of the air whenever I pull my plugs to read them. Some of these guys are running from 28 psi to over 30 psi of boost, so I guess you could say I feel like I'm running mine conservatively. I also spray methanol for more preventative measures also.

good luck!
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Old 03-21-2007, 05:36 AM
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syclone?

where do you you get those upper elbows from ?and the other parts to convert the edekbrock intake? that does look like a easier way to go but it also looks like alot more $$$

Last edited by 12second6; 03-21-2007 at 06:13 PM. Reason: mis spelling
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