I have my 1988 trans am gta torn apart... the heads are at the machne shop and well the wait has me second guession myself.. originally i pulled the car apart to replace the head gaskets and put headers and injectors in it and then throw the nitrous that i have on it. now my father has me thinking with his " you gotta put a cam in it" theory. however my wallet wont allow me to do headers, cam, lifters, locks, retainers, valve springs, and injectors... so if i were to slack.. where should i slack at untill the money allows me to do it all.. should i get a cam and throw the manifolds back on it? or buy headers and not injectors ? while i have the intake off i am doing some porting and what not so the car should prolly have injectors ? no ? please help

 

Do the headers first.

 

Headers and cam ? And leave the stock injectors ? Will it run lean with stock injectors ?

 

Why would it run lean?

 

nitrous, cam, minor head work, and ported intake all on stock injectors.. that could make it run lean correct ? or am i mistaken

 

Nitrous is going to add its own fuel, you haven't got the cam yet, it doesn't sound like you've done anything to the heads but put them back to factory condition, and porting the intake probably hasn't made a tremendous difference.

 

okay, well good deal then.. hopefully ill be safe. perhaps an air to fuel gauge will relax my worries. thanks man

 

Im going to go out on a limb here and respectfully disagree with Aiperon. If I'm not mistaken about the nature of nitous oxide, it is not a fuel source but rather an oxidizer. It therefore requires additional fuel. While this alone wouldn't lead me to go to larger injectors, I would at least check with the manufacturer of the nitrous kit you choose about what sort of upgrades or alterations may be needed to the fuel system to support the nitrous.

As far as needing larger injectors for the engine upgrades you have listed, I don't see the need. A small increase in fuel pressure(adjustable FPR) will make up alot of difference. Pressure and actual fuel dispensed are linear to each other up to about 70 psi. The factory injectors are rated at 19lbs per hour at 40 psi, an increase of 10 psi will raise the effective injector size by 25%, to about 24 lbs per hour. Installing larger injectors will most likely cause the engine to run pig rich.

That being said, I have seen so many injector failures on GM EFI engines, especially the late 80s engines that used Multitech injectors. I would at least pull the injectors and take them to a good injector service to be tested, cleaned and replaced as needed.

 

Yes, which will be supplied by the nitrous kit. (Assuming it's not a tiny dry shot)

 

This is the time to do the cam, a timing set, better valves, and a 5-angle valve job. Everything else is more external, thus easier to change later. Use the FelPro 1094 steel shims to get good quench. Choose stainless 1-piece swirl-polished valves with under-cut stems, and have the shop put 30-degree back-cuts on them. Have them cut the seats as far out on the valves as possible. 7-angle VJ really isn't worth it, so they should start with the standard 3 angle, 30 / 45 / 60, then the sweeper cut should end with a 15-degree, and the bowl hog is 75 degree. That should be as deep as possible without hitting the guide bosses, and should narrow the 60-degree cut until the 60 is about 0.055" wide. If you want to try porting the heads, lightly blend the 75 into the ports, using Gorilla tape to protect the seats, taper the guide bosses, polish the exhaust ports. That's as far as DIY should go with no test equipment. Don't cheap out and use a non-roller cam, nor cheap out on the timing set. Cam selection, assuming headers sooner or later, should be single-pattern for high elevation, or about 6 degrees extra, at 0.050", for sea level. Probably nothing wilder than a 218/224-112 if you like revs and gears, or a 212/218-110 if you like insta-torque.

 

Yes, of course. I should have known you would have thought of that.