I’m not sure if I’m posting this in the right thread. I have an 88 firebird. Pulled out the fuel injection and put Vortec heads with an Edelbrock performer intake and en Edelbrock 650 carb. The car has horrible engine judder when accelerating normally. When I punch it it’s fine but under normal load it shakes like a mother. I’ve never adjusted valves before and not sure if I did it right. I ran it without valve covers and tightened the rockers down until there was no rattle. Tried playing with the air/fuel mix screws. Still no change. New spark plugs. Wires all connected new distributor. Not sure what to try at this point

 

You messed with so many things at one time that now it is nearly impossible to take a guess at what is wrong.

 

Great place to start would be, sit down and take a deep breath.

Next thing would be, whatever you "adjusted" such as idle mixture screws, PUT IT ALL BACK WHERE IT WAS. Undo as much as you possibly can of whatever you did to it since obviously none of that was the right thing to do.

If you adjusted the valves, that's the first thing I'd go back and check. The best way to adjust them is to back each one off, one at a time, until it clacks loudly (you'll know INSTANTLY what I mean when you do it, if you don't already), keeping in mind that if you "tightened them down" before rather than ADJUSTING them, they may be WAAAAAAAAAAAAAAYYYYYYYYY too tight now, and might take several turns to back off to that point; then tighten it back until it just barely quits clacking; go through all 16 as fast as you can, to minimize the mess; then once they are all 16 set to "zero lash" that way, turn the engine off, and add your desired preload which I would recommend ½ or ¾ turn. The exact amount isn't as critical as making all 16 the same. DON'T try to add the preload while the engine is running; that makes the process take several times as long, meaning several times the mess. Then last of all, after putting the valve covers back on and hooking up ALL wires and hoses and whatnot and otherwise putting it ALL back together COMPLETELY, a trip to the quarter car wash, to clean up any oil that escaped during the process.

 

I got it figured out. Runs like a dream now and goes like crazy

 

Good deal.