Hello everyone, I recently rebuilt my 85 Z-28's 305 and replaced the stock intake with an Edelbrock Performer. The original stock manifold had a part number 14057053 on it and looked like a dual-plane design as well. I just wondered if this was the standard LG4 intake or if my car was unique. It doesn't seem to have the bottom-end off-idle grunt it used to with the new Edelbrock. Any suggestions?

If its aluminum, its the stock LG4/L69 intake manifold. Nothing really unique or special about it.

I'm not surprised your Ede intake has a little less kick than the stocker. The stock manifold is designed for low end torque. The edelbrock is more for top end, and sacrifices a little low end to get it.

Yep it is aluminum. So I guess it is nothing special. I hope headers will help the Edelbrock intake work better. I'm saving up for some SLP smog-legal coated ones or Edelbrocks. Just a matter of time. Thanks for the info.

Headers will help. Just keep in mind, you haven't "lost" any low end, it hasn't gone anywhere, it just seems like it because you have more in the upper rpm range now.

I'm a little surprised to hear that. The Performer isn't anything special for high RPMs, either. When I went from the stock LG4 intake to the GMPP q-jet intake (which is capable of higher RPMs than the Performer or stock intake) while the LG4 was still mostly stock, it didn't lose a bit down low.

Did you set the timing to the same place? A few degrees retarded from where it was before will make a difference. You might try advancing it a few degrees more, anyway, and see what it does.

Hmm, didn't notice it was just a Performer. I thought he said Perf RPM.

My edelbrock is a 3701 EGR smog legal Performer that claims to have good throttle response frm off idle all the way to 5500 rpm. I'm just wondering if it is any better than the stock one.
The car runs good, but I thought it was more responsive before. Maybe the timing is too modest now and needs a little advance.

If you had asked before doing it if that Edelbrock would be "worth it", the answer undoubtedly would have been "no".

The typical LG4 base timing call-out is zero degrees. The typical LG4 is pretty happy with 4-6 degrees advanced base timing.

I'll have to stop by the shop tomorrow and see if he'll bump up the timing a bit. It is a real drag to spend several grand and have the car run worse han before. :-(

Hate to get off the subject but if the LG4 "likes" 4-6 degrees over 0 degrees advance , and mine sure does, why didn't GM set it there? Is there an emissions difference, or is it that at 0 degrees you can use lower octane?

phil

Cars are tuned at the factory for emissions, not performance.

Sorry to hijack this thread but I am interested in the GMPP Q-jet intake Five7kid speaks of. Do you have a part number?
Did it affect hood clearance?
Will my L69 air cleaner still fit?

Thanks

This is probably the one he's talking about.

http://www.paceparts.com/index.asp?P...D&ProdID=22352

I'm running one in my L69 car right now with the stock air cleaner. It altered the hood clearance slightly but still fits.

It is far better than the Performer as far as performance. The runners are larger and straighter, and the plenum is taller. They're not as big as the Perf RPM, I'd guess about halfway between the Perf and Perf RPM, just from laying them all out on the floor next to each other.

It supports all emissions features. Whether it's "50-state smog legal" (or even 49-state) I couldn't begin to guess. I know my car passes easily with it installed; but whether it's "legal", as in, does it have a CARB EO #, I have no clue.

Of course, I didn't pay anywhere near that much for it; and you probably wouldn't have to either. People who buy the ZZ4 and replace the intake, have these for sale in basically new condition, all the time.

I got my timing adjusted today with 6 degrees of advance and boy, what a difference! It moves out again! Feels like a Z-28 again! Thanks for all the help!