Hey Guys.

I have an '89 C4 L98 Auto w/ 69000 miles.
The Car is in great shape except for a small oil leak from one of the head gaskets. I plan on taking care of this b4 the month is out.

Now since I have to take apart half the motor to get to the head gaskets.
I want to do a few more mods while I'm in there.

Performance cam, free flowing cats, long tube headers, ditch the smog pump. new water pump etc....

I have a few questions...
1. Cylinder heads. There are a lot of after market heads out there
claiming to out flow the stock 113's. I'm not looking to race the car
I just want to hold my own at a red light. Can I get by with the stock heads? A set of after market heads will really eat into my budget.
and if I can get 300 + horse w/ the stock heads that would be great.
2. Cam. Can anyone recommend one? mild but not too mild?

If any one has already made similar mods and have a combination that worked well.
I'm very new at this and any help would be greatly appreciated.

Thanks.

 

I think the 113's are good for 300-350 horsepower, not sure.

Headers will pickup some good power with a free flowing exhaust

 

1. Headers/Exhaust
2. Cam/ Roler Rockers
3. Intake - Ported base and plenum(or aftermarket), AS&M runners, or modified stock ones.
4. Ported heads

If you do these 4 things you will see large gains and will probably see over 300hp and alot of torque. Your automatic may fail after this though, but they are cheep to rebuild well. If you can raise your compression you will see gains from this also. You are deffinitly on the right track, just use the search function and all will be revealed to you.

Cheers

 

Are you sure your oil leak is from the head gasket. It is unusual for a bad head gasket to leak oil on the outside. It is usually from the valve cover gasket or the ends of the intake or the sensors. But who cares about the oil leak, it's a good excuse to make changes for more hp.

 

With your intended mods you should make >350chp.

To really "liven her up", add a TransGo shift kit plus 2,000-2,400 RPM TC.

 

113 Heads wont make any noticeable difference over what you have now except for weight savings. Stil a small valved head too. If theres any way you can swing it swap cams and heads now you can always change the intake easily later if money is tbe issue.

 

bad head gasket will not leak oil outside of the engine...what you have is a bad valve cover gasket or a bad intake manifold gasket

 

Check the oil sender under the distributor . They leak too.

 

He has 113 heads now.

As for the original question there are several things you can do to improve your stoplight get away.

I would wait on the LT headers and install a good exhaust first. Remove the pre cats, install a high flow main cat, and go to dual outlet mufflers. While you are fixing your VC gaskets install 1.6 full RR's and springs, remove your frisbee and install March aluminum under drive pulleys. Cut your airbox lid get a new filter, and do a TB bypass. Finally, if you have 2.59 gears go to performance gears.

When you finish all this, see how you feel about doing more expensive mods.

 

Stock heads are fine with your power goals.

If the stoplight-to-stoplight racing is your only goal, then it would be gears and a TC. If you have 2.59s, go to 3.07s, preferably in a Dana 44 carrier (only justification for the expense). I would only go to 3.54s in an automatic if you never plan to do much more to the car's intake and internals. I don't like that much gear on an L98.

The stock Torque converter is about 1500rpm, you need something more like 2000-2200 for a nice street L98. If you do these two things the car will feel faster off the line.

Since the engine is going to be apart, I would not hesitate to either upgrade the intake manifold system, or port the hell out of it all. That is a major bottleneck to the heads, which can support more power than the engine makes. I would do the 1.6RR without hesitation either.

A cam change depends on what you do to that intake. If you want to leave it stock-looking, then I'd probably pick a mild one like the Accel 211 or something with similar spec. You should get your chip reprogrammed custom if you change the camshaft however.

The exhaust manifolds are another bottleneck which you'll want to change someday, but I'd wait and do the topside first since its all apart. You may choose to not do that if youre happy with the topside stuff.

 

my 700r4 is holding up to 400rwhp and 430rwtq

If you want tq your on the right track. your intake limited in hp production but tq is more fun anyway

 

Hey Guys.
Thanks so much for the great advice.
I've learned more in the last couple of days then in a whole winter of research.
Let me fill in some gaps.
The car has a BB stainless cat-back system and a K&N filter w/ modified air box and I did have have a mild shift kit installed when I had the tranny rebuilt.
The valve cover gaskets have been replaced but I still have the leak.
My mechanic thinks it's coming from under the head so I assumed a bad head gasket. I will definitely be looking at the intake manifold this weekend "if it ever stops raining"
As far as mods go I think I'll be keeping the stock heads for now.
I'll be searching the forum for past posts on porting.
Also I'm thinking a comp cams extreme energy cam # 08-503-8
has anyone used this cam if so what can I expect?
Now I know that a cam change requires some changes to the computer. Can I use one of the off the shelf chips or do I need to find a programmer?
I'm also going to go with the 1.6 RR's now this may be a dumb question but.... would I need taller valve covers with 1.6 RR's?
can the stock covers be clearanced to fit? does anyone make taller stock looking covers?
I would like to keep things under the hood as stock looking as possible.

Thanks again.

 

mine didnt

 

Too much cam for the stock or ported stock intake in my opinion. That cam prefers something that flows much better. I would go with a little less duration @050"

Off the shelf is worthless, custom only.

You will need to dremel down the insides to make the stock cover fit. You could use taller covers but then you run into the problem of EGR fitment or wiper motor, etc. I would strip the stock ones, dremel out the tabs inside, and repaint them.

 

Mine didn't either! -with shift kit and valve body, new rebuild lasted a year. Had to do a ZF6 retrofit.

 

Run around on sumitomo tires that cants hook under 50mph and nothing ever breaks lol

 

[QUOTE=vader86;1574075548]Too much cam for the stock or ported stock intake in my opinion. That cam prefers something that flows much better. I would go with a little less duration @050"

I was planning on doing something with the intake eventually.
Would too much cam cause a power loss in the mean time?

 

lol...no doubt. put some drag radials on and **** starts to break.

 

I think that particular cam needs a different intake system altogether. I would not run with a modded TPI.

You should not get the cam before you have firmly decided what you want to do with the intake. All of this stuff must work together and you could end up with a bad combination.

I would not say it will lose you any power, it'll make more for sure with the chip tune, but you will not make what the cam can do if you dont pick the right intake system.

 

That is too much cam. Use the KISS method for now, your heads and cam are pretty good for a street car.