where is my power going -rebuilt chevy 350?

Max timing at 30 rather than 28.

Where is lifter pre load..?

You look at base ring of spark plug for jetting, not porcelain.

Jetting should be based on main air bleed size. The smaller the main air bleed, the smaller primary jet it will want.

Adjusted the APT screw yet..? (If it has one)

So you have .040 tipped primary or secondary metering rods..? 72 is a lot of primary jet if it has small main air bleeds. If the main air bleeds are .118, then no wonder it's a dog, and will always be. I'd put .046 MAB's in it and step the primary jet down to 68 or 69.

Put a 3406 Mr. Gasket spacer under the carb.

Where is the float level set..?

camshaftshaun@gmail.com

well first off i would make sure you cam isnt wiped out the the exhaust side, .485 is to much for stock vortec heads, the springs need to be changed and they might even need to be milled down a little for clearance. i built a vortec engine for a 86 z28 and it ran 13's on the stock converter. so i would sau first of get a trans cooler in there so you dont burn up the trans, 2nd i would make sure that cam is all good, i think you would see extra metal in the oil and hear it tapping if you have had issues and you max advance should be 32-36 degrees total advance by 3200 rpm. and put a 2500 or 300 stall trans in it if you plan on running it 1/4 mile because you 60' times are going to be well over 2 seconds with a stock converter. remember the huge 12" converter is just sucking up power so if you go to a higher stall 10" you will get more power to the wheels but make sure you run a trans cooler. sounds like a nice street setup, should do high 13's as is and mid to low 13's with it tuned in and a stall, i would have went 3.73 gears as i always do and with an overdrive tran i would consider 4.10s if you are racing it, if not forget about it. if the idle drops alot after just running you might be still running rich, more gas doesnt equal more power and the stock converter is going to make it idle to low while in gear at a red light or stop sign. i ran all mechanical timing advance on mine at 36 degrees and the vacuum was for at idle to make it run cooler. there is alot of stupid little bugs to figure out when building a car but you get most of it down over time. PM me if you think what i said makes sense and i might be able to help u out some more.

If you are getting 16* at WOT something is wrong. You say the vac can pulls 10, so you should see at least 26* with it hooked up and stabbing the throttle in park.

Vortecs seem to like timing up around 34*, but timing is dependent on the engine. 16 is WAY too low. I hope you have the vac advance hooked to manifold vacuum? It seems you've done some research, I suspect you already know that, but never hurts to ask.

Most likely you'd have other symptoms of trans problems other than just hard throttlem but is possible it's slipping, most of the transmissions were designed for "comfort" shifting, which meant very slow clutch apply, which increases heat and wear when you are hard on it. Note that an '89 Buick 200-4R is going to be "weak", and nothing like the SS/442/GN variants of the same trans. I'd really look at beefing that thing up before you break it, will be cheaper in the long run.

Edit: You want your advance "all in" typically around 3500RPM. You need to figure out how to pull more advance with that thing.

Do me and yourself a favor. Set base at whatever it starts fine at (12*?), then plug in your vac advance. LEAVE vac advance hooked up. See if you can still start it easy. I am not sure why this isn't common practice, but on the EFI side, where you can simply change timing to whatever you want, idle timing is 20*+ (it makes idle very smooth), but drops off as soon as throttle is stabbed under load, then ramps up as RPM's increase.

In your case, as soon as you stab the throttle at idle, vacuum drops, and if the vac can will bleed off fast enough (you can change that with the size of the hole where the hose hooks up) a mech/vac timing setup will work the same way.

Still though, assuming everything else is good, I think timing will be what will make your difference. I've got EFI in my truck, and the difference between good timing, and too little, is night and day. It falls on its face when timing is substantially off. Figure at WOT driving, you are only seeing 16* (vac advance is 0* at WOT) if I'm reading you right, which is less than half what will probably get you good power.

Edit: Thumbs down? Got any data to back that up??

Old fuel should be replaced, it may have gelled up in the tank, the lines and in the carb. The timing chain should have been replaced as well since you done all this work already. If the pistons were a loos e fit, then you probably lost compression too. Check the distributor also to make sure you have it in correctly. #1 cylinder to TDC and on the compression stroke, then look at where the rotor in the dist is pointing to, should be facing the #1 terminal on the cap. If not, remove the dist from the engine and reinstall to the correct position. Do a compression test on this engine , this will tell you a lot about the condition of your valves and pistons too. good luck........

The fact that you don't even know if your transmission is slipping pretty much explains the problem.