my question is what is the ratio on stock rocker arms? I cant find specs in the book I have but while I got your attention can I swap them for 1.5 roller rockers without having to swap other parts? Another question is what makes a rocker self adjusting and is it worth it?

 

Stock rocker arms are 1.5:1 ratio.

Some brands of aluminum rockers require the following: Rockers for 3/8" screw-in rocker studs and poly locks. Must remove pressed in studs tap the holes for 7/16"-24threadswith heli-coils toinstallscrew-in studs withguide plates.
Guide plates: GM-14011051 (use on cylinders 1,2,5 and 6) You must grind plate to clear valve cover hold down bolts;
Rocker studs: GM-12495497 (3/8"-24 top x 7/16"-14 bottom)
Hardened pushrods: GM-10046173 (5/16" x 7.192") or Comp Cams #7940 (5/16" x 7.200")

Comp Cams Pro Magnum Roller rocker arms, part #1318-12, 1.6:1 ratio, use 3/8" -24 x 7/16"-14 screw-in studs and are made of chromemoly steel. They areself aligning andwill not require guide plates and hardened pushrods. These are the best rockers to use and are especiallydesignedfor 1987-2003 4.3L V6 heads. These are on my "need to buy list" for my 1991 4.3L engine. Cost: $230.00 + shipping.They will probably be one of the last things I buy because I can install them in 30 minutes.My engine builder does not needthose.I you don't install 1.6:1 ratio rocker arms, you gain nothing. There is little or no advantage between stock 1.5:1 rocker arms and 1.5:1 roller rocker arms.It is a huge waste of money and time to install 1.5:1 roller rocker arms. You will never know the difference between stock rockers and 1.5:1 roller rockers except for more noise. Roller rockers are wear out and are more noisy than stock rockers due to the rollersmoving back and forth. That is why Comp Cams #1318-12 chromemoly steel 1.6:1 roller rockers are rebuildable.

The higher ratio 1.6:1 ratiorockers are a plus for the 4.3L V6 engine because they increasethe valve lift acceleration rate for faster low RPM cylinder filling and more low RPM torque. Those rockers used with a stock cam (for .386" I /.424" Evalve lift) or a GM-10051147 replacement cam (for .494" I/E Valve lift) is agood combination. The latter camshaft needs GM-3927142 valve springs for best performance over 3000 RPM due to higher valve lift.

 

The stockratio would either be 1.5 or 1.52 as for self aligning unless your heads have guide plates you need them. Stock heads don't have guide plates. If you want non self aligning rockers you need plates and hardened pushrods. To put guide plates on you will need to put screw in studs on the heads. Just stay with a self aligning rocker either full roller or roller tip.