i have a 99 tahoe 5.7 without a.i.r. im buying edelbrock headers?

You might want to check with: Pertronix Performance Products before purchasing headers from Edelbrock.

Pertronix recently bought out Doug's Headers and I personally can tell you this much: They fit great and have every necessary emissions fitting necessary if your Tahoe has them. It's not necessary to lift or do anything special to toss them on.

Don't do it!!!!

you want some awesome headers that leaves access to the plugs and has more performance than most others.

I strongly suggest that you check out the following. I have talked with the owner and am aware of the results against other brands on a Dyno.

The headers you want for your 350 are made at Stan's Headers, in Auburn, WA. They are called "tri-Y" headers and are awesome for small block Chev engines. They make them for Ford and other manufacturers as well, But I saw the engine in Stan's brothers old '56 P-U with the tri Y's and he also told me he got around 35+ Horse Power increase just putting those headers on.

Stan's is a full featured Exhaust manufacturing plant and has been in business since as long as I can remember. You can google the products and they are custom built to the application.

Google Stan's and give a call. They are friendly helpful and will answer all your questions.

Please don't use edelbrock. Also, a good high flow after market converters such as Magnaflow Performance (I usually put a larger bore on them like 2-1/2" or 3") will increase the flow as well. Depending on the HP your engine gets, Stan's Tri-Y headers with 3" front pipes, 2 - 3" high flow converters, a pair of 40 series flowmasters or try Terminators (similar to flowmaster with a deeper mellower tone and lifetime guarantee - solid welded cases) and 2-1/2 or 3" axle pipes with 5"X18" stainless tips is a great system for SB GM engines. You may have to put weldable threads for 02 sensors on new front pipes, but if you want no restriction and great flow, thats what I would build.

If you use a cold air filter element such as K & N, go easy on the oil. GM has sensor failures due to oil contamination if the oil gets into the intake snorkle.

and eliminating the belt driven cooling fan and clutch and installing a good electric fan will give you additional HP and better mileage, taking some load off the engine. Those changes can give you awesome performance at reasonable cost.

Stan's Ph. # 1-800-962-6467

Link - http://www.stans-headers.com/tri_y.htm

on a 99 it will be a pain to putin you might even have to pull the motor set in the headers and then drop the motor back down. call the edelbrock company and they can give you better advice