Hello I am the new owner of a 1987 C-4, A friend of mine had it setting around for about 4 years now and offered it to me at a price I could not turn down. I have ben lurking around here for a while now and found it a wealth of information. I am now as we speak having the high milage. L-98 swapped out for a 383 stroker. Ok so here is the question How and what do I need to properly set the 383 up. I have been reading about it but I am sooo confused, Please set me in the right directions
Thanks in advance !
Jerry B

 

if its running good , dont fix it, its ok

 

Highly unlikely the stock L98 tune will be compatible with a 383

Depending on what you have now, most likely will need a new tune in the computer to adjust for the changes ( bigger injectors / cam / etc ?) you have made
Custom tune ( chip ) from PCM for less or similar
you just send them your engine specs

http://www.pcmforless.com/index.php?...id=2&Itemid=43

 

i was kinda figureing whoever installed the new engine may have done the tune at the same time. I wouldve.

 

Ok,
Last week I installed a 383 in my 86.
It goes like a bat out of Hades, BUT:

It would not idle and right off of Idle, it would not run well.
I retarded the timing just a little, and I installed a 52MM throttle body.
WORLD OF DIFFERENCE!!!
I set the idle at 800 RPM in park, and it idles just fine in drive. 650-700 RPM.
It seems to have no issues just the way it was with the 350 in it. Course, I have not run it flat out, since the engine has about 5 hours on it, but all indications are, that for the driving I do, the existing tune with the larger throttle body is just fine!!
My MPG readout is at 19.9 mpg, and seems to be working it's way into the 20 mpg range.
Since I have only about 5 hours on it, I haven't got much to tell, but there is a story behind it:

The engine was bought in a wrecking yard for $300 from a burned 88 corvette.
I could see through a burn-thru hole in the rocker cover that someone had put roller rockers on it, and so I asked how much for the engine. I was told $300, so I bought it.
Turns out, it is a 383, and someone got the keyways mixed up on the crank, and it was 8 degrees advanced, and the heads on it were swirl port heads........didn't make sense until I tried to put 113 heads on it, and the intake valves hit the pistons on every cylinder. The problem seemed late valve timing, and my machinist told me "read your cam card!!!!" like 5 times to every question I asked. So, Since the cam was brand new, and it degreed wrong every time,
I had a stock timing chain, and I put that on, and Voila! problem solved! The previous owner misread the directions (or not at all) and put the timing too far ahead.
I installed file-to-fit rings in it after honing it, the bearings looked and mic'ed brand new, and so I just put it all together and ran it on my engine stand.
So I had set the engine aside for the truck I have.
The 350 I installed in the car was pumping oil on # 6&8, So I put the 383 in it.
So, I now have an 86 early corvette with a 383 4 bolt main full roller block, and it has buckets of torque.
THe car is so much more of what I expected when I bought it in the beginning.
I am beginning to wonder why I didn't do it sooner, and why I ever built a 350 when inexpensive 383 kits are out there.

Ok, back to the original question.

I just changed the throttle body to a 52MM BBK / Edelbrock unit, ported the original 113 heads I had, ported the exhaust manifolds, installed true dual exhaust pipes with dual cats, and 91 convertible mufflers, with a '92 firebird trans made to work with a corvette.
I installed C5 front brakes on it, and stickier rear brake pads with C5 wheels and tires.
it is sooo sweet right now.
Soon I will have almost 500 miles on it, and I will stomp it when I get a spare trans ready.
I also have a 307 rear for it just in case I get tired of the 2.58 rear.

Oh yeah, with a 160 thermostat, it runs at 175 degres on the freeway, 196 degrees in town, If I just let it sit and idle, the computer turns on the fan at 236 degres, and it turns it off at 215 degrees.
With the A/C on, it turns on the fan at 220 and off at 205 degrees.

The only down sides here is that:
1. I painted it orange to put in the truck, and I wasn't going to tear it all apart and paint it black.
2. I need to put a corvette servo in the trans and the corvette flyweights in the trans governor.
3. I have to work and can't fiddle with it every day all day till it's done.

 

Thanks for your info, Do we need to put the O2 sensors in the headers for the TPI, and there will be no cats.
Thanks,
jerry b

 

An 87 has a single O2 sensor that is usually installed on the drivers side header and is required for closed loop mode (cruising). No cats wil make it breathe better.