I stand corrected, every blazer I've encountered was a 305 or 2.8....

 

vacuum dropping when wot is a bit intriguing. never heard of that. does the carb use vacuum secondaries? could be something wrong with them. but if its going to 25" of vacuum when wot, there is something seriously restricting the intake as an amount that high is usually only achieved during decel

 

Yeah i believe it was from the K5 Blazer. Ment to put that in the last post but it slipped my mind thanks for the replies though guys keep them coming i check the page about every hour

And microkid i change the air box from stock to a K&N 63 series high performance air intake from summit racing and the vacuum when i floor it gets to about 18 psi so not much diffrent car runs a little better still no acceleration or tire chirp though keep the posts going thanks guys

 

I had my sister drive while i watched the vacuum and every thing and when she floored it i mean petal to the floor the vacuum dropped from 9 psi down to 4 psi and stayed there till she let off and we went from about 25mph to 30mph and it took like 10 sec to do that something on the car is really not right at all it has a rochester quadrajet and im pretty sure the screw on the front(ill post pics tomorrow) is called the lean screw and can it just be leaned out or is it something tragically worse? HELP!

 

Like I said before, what the vacuum is doing is NORMAL, provided you have the gauge connected to manifold vacuum. Manifold vacuum drops when the gas pedal does, it's the nature of the beast. The screw you're talking about (there are two) are the idle enrichment screws. If that's what you're referring to, they are in the front carb base plate. They affect your idle fuel richness, not "open throttle" performance.

 

No the screw i, talking about is circled in the picture. And if the vacuum is supposed to drop like that wheres the power in the beast

http://i55.tinypic.com/2ik9rx4.jpg

 

This is what I'm seeing. You are worried about vacuum drop, why? It is normal as camaro69 stated. You still haven't answered my question on whether or not you have a 350 vs. 305, why is this even important? Well, I am thinking you have a emissions controlled 305 (or 350) put into your car with a cobbled up Q-jet that may have missing, damaged, or unconnected vacuum lines, also, as stated before those carbs, particularly the early to mid 80's do not have a lot of adjustability and some were electronically controlled. For example, how does your secondaries open on that model? is it mechanically, or by a vacuum plunger? I'm just trying to figure out what exactly you have, vs. what kind of power you think you ought to have. It is possible that your dad's stock 305 is indeed better of than what you have (if its been cobbled together).