Here is what I've done so far:
1 - Removed the old temp controlled air cleaner and went to a 12" Edelbrock filter.
2 - Put in a Curve Sping kit into the dist and went with the black springs - the lightest ones. I don't know why. How do I determine which springs to use?
3 - Installed Dynomax Headers
4 - Changed to true duals (2.5"), no cat. with a cross pipe about 6" behind the cross member.
5 - Now, for the most disappointing, I put on Dynomax Super Turbo's. I wanted it somewhat quiet but that was too quiet. So I turned them in for their UltraFlo SS and they are just about as quiet. I talked to the guy at Flowmaster and he said it's because my L48 is just too weak and my 2.5" duals are way too big. He doesn't think Flowmaster's can help. That is disheartening news to me.

So, what's next? A carb and intake? What kind? I don't want to drag but I don't want to be Mustang bait either - HELP!

 

There is absolutely no way of making an intelligent recommendation to you without knowing what your goal is!

Soooo....what kind of output are you looking for? 250hp? 300? 400? or ?

 

1) Cam
2) Heads
3) Intake/rejet carb

 

I'm not too surprised about your exhaust experience. I wouldn't have thought it myself either, but when I swapped my old L48 out for a 383 I had built . . . The same puny exhaust pipe into dynomax super turbos is actually pretty noisy now. In fact for most people it would probably be too loud.

If you are just looking to make noise, why not go to glass packs, or just straight pipes with no mufflers? Also the cross pipe will change the way the exhaust sounds a bit. . .

Make it perform better? What is your budget? A relatively inexpensive upgrade would be to swap in a different cam. A more expensive route would be to drop in a whole new engine. Sorry, too vague

Oh yeah, also, what rear gears are you running? Getting steeper gears will likely make the car much more punchy if you have the same 3.08 freeway gears that I have on mine . . . Maybe some 3.73s or something . . .

As for the timing curve, Lars wrote a good tech paper on the subject. I'm still not clear on a couple of points myself, but you can read his paper and I'm sure you'll know a lot more about the subject than many do afterward. I don't recall the URL off of the top of my head, I'm sure someone else knows it though. If not, I can check my bookmarks when I get home tonight and get back to you.

-dath

 

If you don't care about numbers matching or anything like that then remove the motor mounts and tranny bolts & replace the engine. You can get a nice 300HP ZZ4:

specs can be seen here at gmpartsdirect.com:

http://www.gmpartsdirect.com/perform...ATID=1099.html

You can order it from Boaz Alabama at KILPATRICK CHEVROLET on 1134 HWY 431 phone number: (256) 593-4253. I think the going rate on the ZZ4 is $4,000, but there are many other options, such as getting a short block and building your own. The truth is that there's only so much that you can do with the L48 until you run into problems...it's not a high preformance engine. Oh...you can do a cam and some heads easy enough and a few tweaks to get the HP up to a decent 300 at the rear wheels, but the ZZ4 will start you at 355HP without breaking a sweat. And, if you run an L48 at 300HP for extended periods you may see some problems in the bottom end due to the fact that it's only got 2 bolts holding the main caps on while the ZZ4 has 4 bolts per cap...along with some other racing tweaks.

OK...so that's like if you have the money right?

If you are like most of us and work for a living then it sounds like you have done plenty already. Why not just buy a heck of a lot of gas and spend some time on the road? I'm a bit biased because I'm doing a front-end rebuild at the present time and am road sick vette style...think home sick and you'll see what I mean.

 

A good set of new iron or used L98 alum heads would do wonders for your eng and not cost an arm and leg. If you could afford $1k on heads, intake and cam you would have a very respectable eng putting 300+ hp.

Do a google search on 'goodwrench series' and check out the chevy hi performance series on building up a cheapo GM crate eng which is basically a L48 eng all the way to aover 500+ in about a 8 part series that starts with low buck mods and works the eng up in steps.

 

It may also be important to note if you go off the deep end and decide you really want to build a screamer that your L-48 2-bolt block is actually *BETTER*. You can have the mains "splayed", turning the 2-bolt into a much stronger 4-bolt (as in stronger than a standard 4-bolt). I don't think that is really the kind of thing you are after though. To me it sounds like a cam and possibly head swap is about the limit on things. Sometimes I wish I had went that route rather than having an engine built. . . Do it yourself and know what was done and have the pride that you made it what it is.

-dath

 

I guess I was a little vague. I don't have a lot of money so a new engine is pretty much out for now. Besides, I don't think the wife would understand me paying what I did for the car and then turn around and sink several more grand into it if you know what I mean. I guess the next steps I could do would be a better carb and intake, then a cam. After that heads if it still wasn't enough for me. What could I expect from these mods in that order.
Stock was 190hp.
Headers, duals, and 1000cfm mufflers???
New intake manifold???
Better Carb???
Cam???
Where would that get me?
There are so many carb's and intakes. I would like to stay EGR. What setup can I get that will allow me to stay with my stock hood?

 

Your modifications should go this way. First the headers then if you want to try to make the stock heads work (that's the cheap way) a street port job and three angle valve job. If you don't want the stock heads now is the time to replace them. Next a MILD camshaft. Then an intake manifold. The stock carb can be retuned for each of these mods.

If you want more than this you'll need more compression. When I say more compression I mean more than the head swap would give you (this means pistons and that means rebuild).

BigBlockk

Later.....

 

There is no need for another engine- many fast Chevys have been built from the normal 350!
Carb- minimal if any over your properly working carb.
Intake- minimal about +10 at best w/ EGR. Al. intake would be a good addition at same time as:
Cam- L-48 badly needs more cam- depending on your trans., (stall if auto), rear gears- a day & night diff. can be made! Over 300 possible.

 

So on a low compression motor like this L48 - it only has 8.2:1 compression - what size cam should I get?

 

The heads can be milled down. Your 79 L-48 spec. is 8.5.
Trans. & rear gears are needed for cam.

 

My '80 L48 runs much better than it did stock (and will still pass WA emissions) with the following mods (mine is a 4-speed, which allows for a little more cam than an automatic, unless you change the stall):
- Comp High Energy 268H
- Edelbrock performer intake (stock carb and air cleaner setup)
- Dynomax headers
- High flow cat
- Dynomax mufflers
- electric fans
- recurved distributer

I don't believe the open airfilter setup gives you any more power than the stock cool air setup. I know I could get some more fun factor if I tossed the 3.08 rear gears, but I often commute in this car and am not ready to bite the bullet for a 5-speed.