swamp21

Ok, I know this has been done a million times, but... I'm looking for a checklist or step by step on an engine swap. Here's the thing... My 91 year old dad can't drive his '84 C4 anymore and is giving it to me. About 80k miles, in pretty good shape, 4+3 manual tranny, & has whatever the performance suspension package was for the year. He bought it new (after selling his '74 Bricklin!).

For sentimental reasons, I plan to hang onto it probably until I can't drive it (I'm 60). But although it's running well enough, I'd like it to have more oomph. Maybe 2x the stock 200 HP would be nice. Considering sticking in a crate motor, from what I've read so far, an LS swap seems like a bit more of a hassle than I want to deal with (plan on doing most work myself). My main question, if I want to retain all "stock" functionality (e.g. gauges, keeping the ECM happy, AC, etc) is there some step by step somewhere of what I have to worry about to plop a gen 1 crate motor in there? Given the miles, I realize it likely makes more economic sense for a fresh 383 rather than a refresh/mild hop up of the existing motor.

Does life get easier if I were to retain the crossfire intake (with a Renegade manifold) rather than go to a carb setup?

Any guidance would be appreciated!

Thanks,
Steve

ctmccloskey

Congratulations on inheriting a nice Corvette! It is wonderful that your Father gave his only Corvette to you to enjoy!

This might not be popular or even what you want to hear but I would strongly suggest that you "learn the car" and drive it for a year or so before tearing into it to make horsepower. Yes, the original engine was not a power house but it works and works well from what I hear on this Forum. These cars were designed by some really talented people and the car by itself is still a strong design that can be modified from here to eternity. I have a 1988 C4 Coupe and I just drive this car and enjoy the fact that it is a Corvette and it handles, stops and goes pretty well. It is a shame when people take these cars and gut them right after getting them because of the Lack of Horsepower issue. My C4 makes 255 hp and it is reliable and gets 30 mpg on the highway cruising along. A buddy of mine offered me a free LS3 complete engine and I thanked him nicely and said "no". I love the way the C4 pulls hard until it hits about 4 k on the tachometer, that is because it has a fuel system designed for a 305 cubic inch engine. The L98 is not an impressive motor but I enjoy what power it makes and it will get up to "Say Good Bye to your License speeds easily". Some of these C4's were very fast in their day. They are not products of the mid to late sixties where you had multiple engine choices.

The one limiter you will find a problem is the hood clearance as Corvettes of this era were packed pretty tight. Sticking a larger more-powerful motor is not an inexpensive task to start with. Look at this forum, there is a person actively installing an LS6 into their Corvette, read about all the things he has had to make or change in the process. Unless you are able to do this work yourself it would be ridiculously expensive.

Take the Corvette, get it detailed and then just drive the car until you learn the car inside and out. Be sure the tires are good and just enjoy the original design. Be sure that the maintenance is all caught up if the car has not been used much. Once you know the weakness' of that particular car you make a list and start knocking them off. There are many owners of 1984 Corvettes who can tell you how to make power and how to optimize your car.

I bought our C4 back in 1998, I had a C3 L-71 car that we purchased back in 1991. The C3 had multiple engine options even between small blocks and Big blocks like mine. The C3 cars have always been easier to update as their engine compartment was made to house a Big Block from the factory. My C3 makes over 500 HP and goes way faster than I care to drive. Yes the power is fun, power can be made in a lot of cars though. I like the power of my 427, it is awesome but now that I am getting older it seems that I went a bit too far. That engine will take my car to 60 mph in less than 3 seconds, it pulls way past 100 mph and it is still going strong. I now want to make it more docile so I can enjoy it as well as my other family members. I have two College age kids and I could not let either of them drive it, it is way too much for a newby to drive. No traction control, No ABS, no shoulder belts and the ability to drop a low 11 second quarter mile time in a convertible.... One nice thing about the C3 was the fact you can change all eight spark plugs from the top of the engine.

I am almost 61, I love fast cars, I also love a car that handles well. Corvettes are very special cars, whether I am driving my '88 coupe or cruising in my '68 people always notice that it is a "Corvette". I get little Honda's that want to race me in either Corvette and I just laugh at them.

Driving a Corvette is something that not everybody gets to do, enjoy it for all it is worth. Drive that Corvette until you can't climb over the sill and enjoy every mile like it was the first time you sat in a Corvette!

I hope that this is of some help to you! Ask away, there are some incredible people on this Forum and a lot of 1984 Cross-Fire experience in particular.

I wish you and your family a Very Merry Christmas!

Chris

drcook

Being a 1984, that car came with a Dana 36 rear end. Starting in 1985 the stick cars got the Dana 44. The 84's got away with the D36 most likely due to the lower HP. If you go increasing the HP, plan on swapping in a Dana 44 assembly. So add 800 to 1200 on to the cost of your build (depending where and when you can find a Dana 44, which you MIGHT need the driveshaft and C-beam, one of the folks that knows the lengths of the components in the 84's will probably jump in).

The Dana 44's were much stronger. If you (OP) up the HP a lot and dump the clutch a little too hard, the D36 tends to fail.

JoBy

I think that the only thing the digital dash get from the ECM is instant fuel usage. The dash calculates instant MPG, average MPG and fuel range from that.
If you want to swap engine and keep MPG functionality then your only option is 1985-1989 TPI that uses the same data stream to the digial dash.
The TPI will get you a bit more HP but not enough more to make it worth it. To make it right wou would also have to get a newer hood and radiator assembly.

swamp21

Chris, thanks for your extensive comments. I've driven the car a reasonable amount over the years (particularly this year as leg problems have prevented his use of it) and am pretty familiar with it by now. Do I really need any more power? No, I certainly don't. I've had an '83 TransAm from new with the LG4 engine (talk about a dog - 150HP stock!) and toyed with the idea of upgrading that things power many times over the years, it just never was a high enough priority. Dad's C4 is quite a bit snappier than my T/A, but handles a LOT better. I'll be selling the T/A in the spring - which ironically seems to be more valuable than the Corvette - so will have some money I can direct to the project. I'd just like the power to be a bit more in line with the handling, I guess.

Probably some top end bolt on stuff (cam, heads, intake manifold) would be adequate to scratch the itch and keep the originality a little more intact. I'm just starting the research so have no preconceived ideas, and there's certainly a lot out there to digest.

Anyway, all comments are appreciated!

Steve

billschroeder5842

I had a XFire like yours in a 82 that I had. I really liked it. Here is my .02

Don;t get hung up on chasing HP numbers. The more you modify you will introduce drivability issues
Th eL83 engine needs to BREATHE, BREATHE in and BREATHE out. If you do some simple bolt ons you will get 70% of what you need for 20% of the money of a full on build.
Put the Renegede on the engine, bump the timing to 10-12. Then put a set of headers on the car and swap the catalytic converter for a Hi-po one and leave your factory muffs. You will have zero drivability issues and add a bunch of power.
Swap you 84 fuel pump for a 85-89 fuel pump. It has a higher fuel pressure so you engine will get everything it needs.

Start here and see how you like the car after 3 or 4 months

84 4+3

If you're feeling adventurous you could port the stock unit. Just being able to rev past 4500 with the ported unit is amazing. The car will feel a heck of a lot better when you do that. It may only be 30 horsepower or so but the extra 1000 rpms is a nice plus.

As for the D36 on 84s, much like everything else, I'd guess the D44 wasn't production ready yet. Just my 2 cents though.

NitrousSam

There are a handful of great options available for you and a lot of this is going to depend on what your "real" goal and budget is. If your primary goal is feeling a sizable increase in the "seat of the pants" when you are going through the gears you actually may want to reconsider your goal and shift from a focus of building horsepower and concentrate on building more low speed torque. Your crossfire setup is obviously your limiting factor in stock form especially relating to horsepower because it is going to keep your rpm range down fairly low However, that isn't all bad if you are going to focus on building low end torque.

zachaeous

Here is what I did to my 84. I ported the stock intake. I mean I really ported the crap out of it. I rebuilt both throttle bodies and installed new injectors. I replaced the camshaft with the old GM 151 327-350 HP grind:327 350 hp camshaft specs. CS-179R Sealed Power brand.

Cam Style: Hydraulic flat tappet

Basic Operating RPM Range: 2,200-5,200

Intake Duration at 050 inch Lift: 222

Exhaust Duration at 050 inch Lift: 222 Duration at 050 inch Lift: 222 int./222 exh. Advertised Intake Duration: 290

Advertised Exhaust Duration: 290

Advertised Duration: 290 int./290 exh. Intake Valve Lift with Factory Rocker Arm Ratio: 0.447 in.Exhaust Valve Lift with Factory Rocker Arm Ratio: 0.447 in.Valve Lift with Factory Rocker Arm Ratio: 0.447 int./0.447 exh. Lobe Separation (degrees): 114

I also added a 2500 stall converter.
Fuel Pressure set at 14 PSI
Timing bumped up between 10 and 12 degrees
Cat removed and true dual exhaust.

There are a lot of cars that will out perform it, but it sure does run a whole lot better than it did completely stock and drivability did not suffer.

Whatever you do enjoy your Corvette and drive the wheels off of it.

ex-x-fire

This type of question on 84s comes up about every other month, this is what I'd do. Find a low mileage vortec 350 (96-00), get a vortec tbi intake, and a 87-89 tbi unit. That should give you a solid 60hp. The stock harness & ecm will hook up to the tbi unit because the connectors are all the same. You'll have to choose an air filter that clear the hood, measure carefully. Don't worry about the dana 36, they put them in all automatics through to 96.

drcook

The car is a manual as stated by the OP in the 1st post. If he does what he wants to do (stated he would like a 383, or whatever) with a manual, the D36 is not going to last.

If he keeps it a mild 300 HP or so and doesn't go dumping the clutch and shocking the rear, it will hold up, but as lots of folks have attested here on the forum, eventually it will break.

swamp21

Ok, you're spot on with this. Not concerned about top speed at all, really it is all about how it feels running through the gears. So I guess it is more of a torque issue. In terms of budget, I suppose it's a function of how much I can get for my TransAm, not looking to spend it all - but $3k should be a reasonable number. I'm very mechanically inclined, have rebuilt many motorcycle engines so would plan on doing most/all of the work myself.

Thanks,
Steve

cadmaniac

To keep things a little more cost effective, why not just do a heads and cam and intake change, with headers and exhaust?
That wont cost nearly as much, or be as much work, and wake the car up tremendously. if you need a little more, then get gears and do the D44 swap.

Less work, less $$$, and likely just as much fun. That's just my take on it.

BLKMAMBA

this is the best idea Ive heard.

mine is a 93 auto but even at 300bhp was embarrassingly sluggish due to the lame 2.59 rear axle ratio. my first mod was swapping in 3.54 gears and a 2800 stall converter and man did the car come alive. but HCI combo is alway's a great option

cadmaniac

Head Cam Intake is because it's an '84. That intake and Crossfire is a very low performance design, and came with poor flowing cast iron cylinder heads. That's why so many people at least put a carb on that year. The crossfire intake is like breathing through a straw.

A 383 would be nice, but with all the supporting mods, it could really add up.

Also, if the 383 is an external balanced crankshaft assembly, the balancer might not clear the front frame of the Corvette. I bought a 1984 with a 383, and the frame had been notched because it used the large harmonic balancer.

Nothing like having a cool new engine that wont fit in your car. ugh....

cv67

Do the 383, Renegade intake, roller cam afr head, headers etc
. Buccaneer posts here (in the C3 section a lot) was involved in the development he can really help out with the "how to"

That will easily get you your 400+.....No need for an LS they arent magic.
Guess the ones who grew up on LS engines dont know much about the Gen 1 and the "ls swap" is the answer to all performance issues.

fparkin

glad I don't have deep pockets I brought my 84 , 5 months ago I just enjoy driving it not fast in 1/4 mile but in mile stretch what a ride 130 easy

84 4+3

It's hard to internally balance a stroker crank, you need a lot of heavy metal.
You just gotta be careful with the renegade. Q/C is all over the map still sadly. Porting the snot out of the stock unit will get you 90% of the performance without dealing with exchanging the thing a couple of times for one that is actually cast right. However again, when it worked I was very impressed with how much better the car felt with just a good intakem

But I've pondered it, you could build one hell of a 383 for 4 grand yourself and the thing would be able to take one hell of a beating... I may get bored in my spare time.

swamp21

Hmmm... are the flaws with the Renegade casting obvious right out of the box? Or not until you try to bolt it on? I was debating a phased parts procurement for cash flow reasons, and that was one of the items I was likely to pick up sooner rather than later.

Steve

BLUE1972

I went old school on my 85, used a carb. It's as dependable and any other car and no electrical issues except the dash which works when it wants. Ported heads, headers and just got rid of the MSD box which failed ( after 10 years) - have a spare 1980 HELI Disy in it - I see no difference....

I was going to swap out the dash for regular gauges, but never did.

Just be aware the cooling on these cars is border line, so if you push the HP you may need a better radiator / fans .

I agree a lower rear will wake up the car, but I did the 6 speed and 3:73's - so that is not cheap, but I've had the cat 10+ years.. Did the mods 10+ years ago.