future plans for the '91 GM

[interceptor1985]

"but I think she'll like cat-back duals w/glasspacks just fine"

glass packs are crapola.....get some bullets

[monterey1962]

glass packs are crapola.....get some bullets

I happen to like glasspacks. The '91 and the '89 both run a glass pack on the single exhaust and sound quite nice. S.U. runs glasspacks on the open duals and sounds damn good.

[Archangel]

Cam advance via the timing set. It moves the power band downward a bit, sacrificing some top end. The loss of the top end is pretty insignificant on an auto trans car that wont wind it up high enough for you to ever notice it. Need that low end torque a lot more than the couple ponies up top that you lose.

Mkay, if I ever end up doing a timing chain replacement on my engine I'll be sure to slip the cam gear a tooth ahead, that's about 8* advance assuming 45-tooth gear (less teeth = more advance, more teeth = less advance), how may teeth do our cam gears have? As a matter of fact I was thinking of that with the truck too, should have just went ahead and done it when I had it all apart - just taking the timing cover off on these requires oil pan removal, so it ain't happening anytime soon. Damnit!

[gadget73]

One tooth is probably way too much, enough to make the motor run bad. 4 degrees is plenty enough to make a difference without a major negative impact. If you over-advance the camshaft, the valve timing gets all out of whack, and it will open the valves too soon, so the exhaust valve may shut before the exhaust stroke is done, and the intake valve might open before its an ideal time. Advancing a stock lopo cam is also a bad idea, the torque peak is at some fairly low rpm anyway, advancing that would just make less power, and destroy the already feeble top end.

Who said pulling the timing cover needs an oil pan removal? Only the front few bolts have to come out, the pan doesn't need to drop. Chevy motors are even easier, just yank the 4 water pump bolts, and pull the buttload of little screws on the dinky chain cover.

[Archangel]

Well yeah, I know what the effects of way outta whack cam are, I was just came up with the tooth-off idea based on what those 3-keyway sets do, IIRC 8* is exactly how much they advance the cam.

About the timing cover, well that's what I meant by oil pan removal, you have to get it loose in the front, and since I hate bending metal that ain't supposed to be bent I'd just loosen its mid-sections bolts too. And the SBC also requires that procedure, the bottom of the chain cover still goes between the block and the oil pan, and if you have the thick DANA seals there ain't no chance of it coming out without a serious fight.

[Mercmarquis]

I thought about advancing the cam a lil bit when I swapped mine out, I think I shoulda. The car is a bit slow off the line, but I suppose thats due to the stock 2.73 gears and stock converter.