I was wondering if anybody knew what the timing chain is set at from the factory on a 91 Z28 TPI 305?? I have read in many places that it was set 3 or 4* retarded from the factory and I'm going to put a new timing chain in while I'm changing the haed gaskets and want to ket a keyed set and advance it when I put the new one in..
anybody doing this ? Pros/cons??

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Hecubus
http://www.tweak3d.net/temp/z28.jpg

 

i always thought it was straight up from the factory. if you advance it you'll increase torque and if you retard it you'll increase HP. straight up is a good middle ground between the two.

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ICON Motorsports

1st & 3rd

 

ede is dead on. Most cams now come out with at least 4 degrees of advance already ground in, so I always install dot to dot.

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350 4 bolt main, Speed-O-Motive 383 stroker kit, re-sized rods ground for clearance,TRW Forged pistons,10.7:1 compression,HPC Coated RPM intake, Speed Demon 750 cfm carb,World Products Sportsman II heads,2.02/1.60 valves, Comp Cam 1.6 roller rockers, Comp Xtreme 284 cam,240/246@.050 with .540 lift,Crane pushrods,ATI damper,Proform HEI and MSD6A box,HPC coated 1 5/8 headers, 2.5" exhaust with 40 series mufflers,TH350 with B&M 3000 stall, Powertrax NoSlip Locker, 4.11 gears.

 

Everything I've ever done and read about cams is lining it up just as per the instructions and manual. In some vehicles, they have a washer/slotted cam gear bolt hole system that you can use which will advance/retard cam timing further than what was ground into the cam, but I don't know of anything like that for our cars....

You'd better match up the dots.

 

advancing your timing will increase low end torque and retarding it increases upper end power, as previously stated. the proper way of doing this, from a performance standpoint, is to get your intake centerline and determine what you need from there. for just a general maintainence repair, just lining up the dots works just fine, depends what you are looking for