I've done some reading about the engineering how's and why's on my vette. I understand the intake (and possibly the heads) was restricted to appease the EPA. Also, I'd like to keep the car somewhat stock-like.

With that in mind, would there be any noticeable difference if I:
1. Swapped the intake for a dual 4-barrel intake and keep the TBI?
2. Swapped the heads for a better flow?
3. Port the heads?
4. Last resort - give up the idea and swap in an LS??

I'm not made of money, but my time is cheap to me and I can do the work.

Let me know whatcha think.

Thanks!

 

for ANY of those ideas to have hope...its gonna take a lil money..

2 quads? 4-what? The engine will drown in air/fuel. it can only pull in so much. whatever is left drowns it. quads look cool though...what goes in has to get out. Headers, complete exhaust. It would take a large blower to stuff that much a/f in a 350ci. Plan on a stroker to begin to handle 2 quads. A tunnel-ram would stick wayyyyy up thru the hole in the hood...

LS swap>?? mo money,.LOTS mo.
ECM, wire harness complete, probably custom made. Then the drivetrain upgrades to keep it in 1 piece.

swap the heads? BEST idear YET. You're headed the right direction.
Definately.

Port the new heads? sure.
of course !

better heads...yessir. Thats where you would be making an honest START. But nothing will do anything until you understand that if you do heads, you do intake system AND exhaust. And when thats done you do programming. oh, Cam too.
When you upgrade one end of an engine you have to do equivelent upgrades to the other end. --> in/out.

Lots of good Cross(X)Fired() upgrades in the intake dept. its just $$$$ we are now talking the thousands ya know?
heads alone...close to 1000 + or - a hun or 2. Heads need shop machines to port right...YOU can do intakes and everything else. Its just time.Less money.

intake...same. Plan what gets bolted to what,. what the purpose will be and buy smart,. build a matched top end...not just name brand BS bolted together hoping it likes the next piece. Usually don;t. Seem way too many builds that spent big bucks on someones intake, somebody elses heads and whoevers cam and carb..and ran like crap. Couldn;t under stand why.

"Damn! spent a ton of money on all that $hit...it oughta run like a bat outta hell !"
it should? why? just cause the parts were expensive don;t mean they were the right parts...


exhaust...same again. Exhaust is science. Not marketing hype. Design the system. Build solid basics...like great headers...then fudge on the mufflers if you have to. Without good basics the best mufflers will not help you later on.

cam...depends on what ya wanna do. Its gonna be hundreds...maybe more if you have to swap in/out lifters for roller set up...etc,.


what you CAN do economically and get exactly what you want...is to buy a salvage engine, tear it down and build it back up the way you want. Consult a perfor mance shop or engine builder that KNOWS what to look for and NOT just bolt on random "cool parts" that everyone else seems to have...thats the kiss of death. Not having a design and just buying performance parts without knowing what you want the engine to do and when/where/how and how much.
Ya gotta have a design. A Plan.
Plan the work.

Then work the plan.
Never buy from a shop that is your unpaid advisor. They are there to SELL you stuff. They WILL if you let them ! Most of it un-necessary.

This plan allows you to have some comfort economically since its not a "got to" situation with the car down until this engine gets thrown together. Seen too many like that and it never turns out well.
You can make adjustments this way. You have the luxory of time being on your side. You build a strong bottom, you decide you may someday go with spray...you CAN now. Or you can run NA if you want...no harm no foul. Its worth it to build stronger than your current needs...The needs will change.

You gonna do strip or street? Street likes big low end power. The strip likes it up high. Plan it out.
Twistys? the right suspension and brakes for sure. This stuff goes hand in hand with a big engine. Gotta think it thru...

The good news is that whatever you do to a CF motor will be a step up. GM was exiting the dark ages (70's) of radical changes in emissions and mpg. new standards that nobody was prepared to meet...so the cars suffered almost as much as WE did...The CF engine was a stud at the time. Now, its a grocery getter in its stock configuration. That CAN be improved upon but it takes MONEY...

Think about what you want it to do, and research the parts, make a design and make an outline on the calendar.
If you decide to piece-meal the deal and drive it as you bolt on stuff.....thats got risk because you;re wearing out things as you wait to install others and you will not ever know what the engine is capable of without a new "tune" each time a major part is installed...

Thats why I like the idea of a 2nd engine. It gives you time and breathing room and engines are cheap.
You can get a good running long block for <$1000 easily. I've seen good running low miles sell for $350. ya just gotta search and be patient and be prepared with the cash when the opportunity shows itself.

One little piece of advice that I think everyone will agree with....
don't be sucked in to the aftermarket HYPE.....the stupid claims of mo'power...14 mo HP just by looking at our product. 27 mo HP if you bolt it on with our super fast high speed flow dammit thingy. Another 19 hp if you use our flowed, polished and tested throttle do-dad.
uh-huh.
After you add up all the BS HP claims, you can easily get another 150HP out of a stock CF motor and never even have to pull a valve cover to do it ! AND.....the money you spent there could have build a damn fine engine that REALLY does produce a mo-power !

You;ll figer it out....just be for warned...Corvettes and performance is like crack. One hit and you;re hooked and it don;t ever get to be fast 'nuff...There will always be something else that you want to do to it. Once you start...you never stop.
Stung by the go fast bug.

Seriously...
I'd start with exhaust, then go to heads, intake and IF you want to do some real HP...plan on a teardown and look at cams, stroking, forged internals...for the next step..getting BLOWN !

have fun. its only money.

 

I looked into this when I had my 84.

The stock heads suck - don't waste time and money on them. Best bet would be a set of basic Edelbrock heads that have an exhaust crossover so that you keep the EGR working for smog reasons and also to keep the computer calibration.

Port the stock intake - when you think you've taken out enough material, take out more. Lots of picks on this subject, mine are on Facebook: https://www.facebook.com/media/set/?...7675337&type=3

Better exhaust (headers) would be helpful since you don't have pre-cats on an 84, but they are still not "technically" legal depending on where you live.

Get Flowmaster direct replacement mufflers - 425501-L and 425501-R

Get a good fuel pressure gauge and make sure the pressure is where it should be - at least 13 psi.

The injectors are probably full of junk. They're super easy to change and the only place who carries the gaskets anymore is FIC - www.fuelinjectorconnection.com

If you want to get into a cam change, that will help a lot but it's a big job. Make sure to keep it mild as the computer can only deal with so much.

Don't waste your $$ on a Hypertec chip.

Other will chime in with more info, so stay tuned.

 

First, Don't waste any money on the existing heads.
Secondly, what gains are you looking for?
Typical free mods on the 84 are:
Cold air mod
Port your existing intake
fpr mod
Done correctly you will see gains of 30-40hp

True dual exhaust-
2500 tq convertor

That alone will wake the car up.

Don't bother with cams/head at this point if you don't have the funds.

 

Thanks for the replies.
Let me explain a couple of my thoughts.
The crossfire is basically 2 throttle body units that bolt in like carbs, correct? The original intake is a weak design, correct? If I'm understanding things correctly, swapping out the original intake (and heads) but using the crossfire injector units in place of carbs should result in significant improvement, and upgrading the injectors would help even more - am I right or am I missing something?

Thanks.

 

You could also swap over to a GM truck tbi unit, the 87-89 350 tbi have the same sensor connectors minus 1 iac, your stock ecm will work w/ it. That lets you use a traditional 4bbl. type intake w/ a tbi adaptor.
Anytime you start swaping intakes on these C4s (unless the intake was to made to fit) hood clearence is very close. Do your homework there & measure before you pull your stock stuff off.