Thanks. I had a ZF6 in that car. One of the best mods IMO.

 

Ha ha...you know that was Jim's car...right? IDK why he never posted that vid. He's gone now, so I took the liberty. I think it's a pretty cool. Even though the car wasn't making it's best passes that day, Jim was pretty pleased w/himself, getting a lightly modded LT1, heads up.

 

I happen to know where that particular car is, And it is still running. parked for the time being..

 

i knew exactly who's car that was... but I had never seen it in action. That was the first.

 

Well it turns out the car has already been modded to what you guys are suggesting with porting the intake. It also has a chip and a full exhaust, got lucky but when I went to replace a gasket on the valve cover today I started the engine up after completing the work and it is now idling at 17-1800. This is not how the car was before the work was done. There are no connectors missing and I cant find where a vacuum leak can be coming from. I am stumped, I have gone over the engine about 6 times and can not find anything wrong. Has anybody else had this problem with the engine?

 

Two centsin. I had an 84 and did some moddds and was satisfied with it.Had it for nine years. First I put an 85 Fuelpump Bosh platinum plugs Accell Ignition under drive pullys A I R pump eliminate it 160 thermostat elininate CAT muffler elininators allminum radiator K&N filter A D S chip {no longer made}and BEST was a HOMEMADE RAM AIR setup. In front of the radiator the soid plastc CUT a hole with a dremel to MATch the hole in the HOOD . Mine worked likea vacumcleaner I had to put a screen under the front air dam it was sucking air so good. I added a T C I shiftkit . I tell you it was real good I could smoke the tire at will Try it I did this little at a time there is a CRoSSFIRE website I was on

 

Try spraying something combustible around the areas where vacuum leaks could be; plenum lid, intake to head flange, PVC, Brake booster line, MAP sensor line etc. Or Propane works too. When you find the leak the engine will change in RPM/sound.

OR go drive it above 30 mph to re-set/bottom the IAC motors. It would an amazing coincidence if a problem arose after valve cover gaskets...that was unrelated to the R&R'ing of the valve covers.

EDIT: How do you know the intake has been ported. I'd be shocked if it were completely/FULLY ported. I'd guess that it's "port matched" which only shows you about 1/2 the benefit.

 

It has probably been port matched. I took the air cleaner cover off along with the air filter and noticed that it was way too clean for the age of the car and the intake was wider than others I have seen. Turns out that it was not a vacuum leak I just had to reset the ECM. Turns out I accidentally disconnected one of the IAC's, so problem has been fixed.

 

wider?.. intersting.
Is there any names stamped on the intake?

 

I didn't think to look for a name. Next chance I get ill take a look and see if anything is there.

 

It kinda makes me wonder... you say the ports are real clean and its wider.
does it look like this?

www.camaros.org/crossram.shtml

 

I have a question related to the 84.

What's the general consensus on the swirl plate in the intake cover? I opened up my throttle bodies and machined out the ports but I left these diverters alone.

What are pros and cons?

 

Swirl plate removal:
"Pros": Better Airflow. Unmeasured, and unsubstantiated, but reason says that nothing in the way flows better than something in the way.
"Cons": Poor fuel distribution and puddling on the plenum floor. Now read on...
There isn't a "General Consensus". There are some who left them, some who modded them, and some who removed them entirely. I think that each person feels that what they did, was the best way. No one that I know of has done back-to-back testing on just that one item, so in reality, we don't know what way is "best".

Here is MY .02; I removed them completely. I "get" that they're in there for better fuel distribution. However, with mine removed my plugs read about the same as stock, I still got 24+mpg (Better than stock) and it idled like stock (even with a 224/234 cam -in a 400). So was I "missing out" on distribution? I don't think so. Not in any meaningful way. Again, realize that GM had to meet criteria that we don't have to and don't care about (emissions criteria, mostly).

What I did was radius the underside of the lid and take that up into the TB's a little -like an upside down "velocity stack". Idea here was to slow the A/F mix as it enters the plenum and allow it to spread. If you simply remove the swirl plate assy, the straight diameter "tube" that is the TB bore and plenum TB hole fairly shoots the A/F mix at the floor of the intake. And even more stupid, IMO, is how the swirl plate assy itself, extends the "TB bore" down another 1/2" into the plenum! My way allows the A/F mix to start spreading and migrating toward the various runners. 3/4" to an inch higher up than the stock location at the swirl blades did. Anyway, does my idea work? The numbers seem to say so. Here is a pic:

^After grinding on it with a die grinder, I smoothed my work with a brake hone and it came out pretty good, I think. I think this is the "best" b/c it offers zero restriction, and I saw no meaningful degradation in drivability or fuel economy from the removal.

Another idea that I saw that I liked was leaving the plates in, but cutting out ~98% of the diameter of the "tube" part of the swirl plate assy, so what was left were tiny, skinny tabs hanging down to hold the "fan blades" in place. You could even combine that philosophy, with my philosophy of the radius.

 

i ported my cf intake, didnt do much for power, it seemed to me the system was calabrated for 9:01 compression, stock cam. the large open plenum and small runners open near the top of the combustion chambers, im sure it underwent a lot of testing, it made a trouble free, gooding running, good reving engine. it was one of the only things that didnt give me trouble, i converted everything, cut the wires, removed computor, got some aftermaket heads, torker2 intake, comps magnum 280h cam, holley 650dp msd 6al and dist removed smog pump, measured for a smaller belt energized overdrive switch with a hot wire from ignition because my car has 4+3 tranny, by the way tranny works great now just have to change fluid often. made a custum dash with analog guages, i love the 84 corvette like it more than every car iv'e ever owned . went from 15.5 at 90mph to 13.3 at 108mph i've got 3 vettes 78 84 59 modified them all and i love them all. i like them old so i can work on 'em.

 

Thats a pretty good improvement, but that put you about the same performance level as me, Dom, QWS and others, still running stock (ported) intakes or other CFI-based, EFI intakes/fuel systems. Ben73 is running lower/mid 12's with his CFI/Renegade topped 383. Not putting down what you did; those numbers are great...but you can get there while retaining the CFI platform, CFI appearance, and all the benefits of EFI in the process.

 

I tried both w and w/o the swirl plates. I found that cold weather driving was an issue. Finally decided to mod them by removing as much of the sidewall as possible while retaining and straightening the vanes.
I also used a plenum spacer increasing plenum size and softening the radius required for the air/fuel flow entering the runners. I used injector spacers for similar reasons.
Of course the runner "roof" was also cut back 1/2-3/4".
Rather than porting the runners, I had the manifold Extrude Hone'd but didn't eliminate the EGR channel.

 

^And that's how it goes w/swirl plates! Mine needed a little "manual throttle"...when it was below 10*F on a cold morning starts. Needed that for about 30 seconds, then, it was fine. So not a meaningful "problem" in MY case, but as we can see, results vary.

I also tried a plenum lid spacer, but in my case, it didn't help in any measurable way...but did add vacuum leaks so I go rid of it. I did like the IDEA of getting the lid/TB's up higher...just didn't work out for me. I used plastic which wasn't good. Aluminum would have worked a lot better.

 

Well just an update guys, decided to just keep the car stock and work on a new engine. Picked up a 95 LT1 for $140. It really needs a rebuild and plan on doing an engine swap once the rebuild is complete.

 

Keep it stock, and get that cheap classic car insurance.