I am considering replacing my 86 305 iroc tpi with the edelbrock runner/ baseplate / plenum. But, money is a slight problem right now. What i am wondering is can i buy it piece by piece and replace one componet at a time (ie: runners first) will it bolt up to stock componets, or will i do more harm than good with this approach. Should i wait until i have it all , or can i indulge my impatience and replace a part at a time?

 

I'd do base and runners at the same time (a lot of work for either). Plenum just needs a little massaging with a die grinder to fit the runners better and knock down the EGR baffling behind the TB in the plenum. Your MAF system should handle the mods without much problem (of course, i would still recommend doing your own chips). Just make sure you get the right parts for your year, and install the runners on the correct sides.
Just remember, Ebay and Classifieds are your friends when money is tight.
And if you're ambitious, throw a cam in while the intake is off, and do the timing chain, pushrods, rockers, studs, and springs at the same time, hehe (snowball effect, sorry). All of that will work on a 350 in the future. Doh, you probably don't have a roller cam in the 86 though, so maybe save valvetrain stuff for then, hehe.

 

What do you mean by "massaging" the plenum? Do you mean opening up the ports, and if so, how much?

 

The new runners have bigger openings obviously, but the plenum openings fit the old original runners. They need to be ported to fit the new runners to take full advantage.

(as far as "fit", they will bolt right up w/no problem, I'm simply talking about optimizing airflow!)

Also, if you take off the throttle body and look into the 2 holes in the front of the plenum, you can see a ridge just inside the plenum along the bottom. That ridge also needs to be ground down to help with airflow.

 

thanks guys. i can see how that would help