Hello everyone, Im new to this and just got my first Vette its a 76 stingray and I am so happy with it. I have a question? The motor is the stock L48 and I want to get some more HP out of it but on a real tight budget right now. Iv heard you can get "bolt on" parts for it like intake or headers stuff like that to get a little more HP. Any and all suggestions greatly appreciated.

 

The best, and cheapest, way to get horsepower is to make sure the car is well tuned. New plugs, good wires, solid spark, good timing, good advance curve, and good carb jetting relative to the timing and advance curve.

Outside of that, you're barking up the right tree. An engine is an air pump and the more efficient you make that pump, the more power will be freed.

Intake and exhaust are obvious low-hanging fruit. Remember, though, that as you change the engine, you'll also need to address the advance curve and carb tune at each step to optimize.

Before you go deeper (1.6 rockers, cam, etc.), I'd personally consider looking deeper into the engine and try to establish your valve-to-piston clearance on what you have now. If it is a low-compression engine, you're PROBABLY OK, but it never hurts to find out.

To make power, you need to spend money. That's the near and far of it. With all new, mostly name-brand components, I'm about $7,500 into my solid-roller 'monster' 350. It is still a true 350 (no bore, stroke, or hone) but I figure I'm conservatively sitting on 450 horsepower. That is with the old Winter's aluminmum intake and a tune I'm still tinkering with.

As you get money, you can address different items...heads being a big one. Compression being another. But you may get tired of pulling the motor in and out, so you'll end up either saving up and doing everything once, or doing everything once and paying off the 0% credit card balance over the next year or so. Your choice.

You can probably scratch another 50 horsepower out of the engine with some 'bolt ons' and a good tune. But that's about it. To get real power, you need ot make real changes. And that takes real coin.

Them's my thoughts.

 

Your semi lucky, I got the Cali 305 worst out the them all. L88 was the best but your L48 middle performer benefits from a free flowing exhaust with hfc or if you don't get inspections no cats. There are nice headers with straight through exhausts that can be made up. Then edlebrock Manafold with 600cfm performer carby and good air filter. Make sure u have no vacuum leaks , spark plugs are gapped and clean, compression is all good, good fuel filter and then timing can be adjusted. If u have $ left over then u can look at heads with better valves and a good cam.

 

Thanks for the reply and advise. I have plans to build the motor out eventually but no funds to really do it the way I want to so I figured I would just go as budget friendly as possible and just do the common bolt-on's for now. I have a 350 4 bolt main that I want to build a 383 stroker with but thats going to cost me and cant start yet so I figured why not get what I can right now from the stock L48 on the cheap without getting into the motor.

 

Mine came with I think a cam as it sounds like it does , straight through exhausts, edlebrock intake and 600cfm performer carb. Not sure about the heads , maybe they can be identified by number somewhere or taking off the covers. Either way add up all the costs to get To your power inc machine costs ect and then see if it's cheaper getting a crate engine. But check your car runs right and plugs, vacuum, writing, fuel, plugs ect is all perfect then tune before u bother putting bolt ons on

 

Thanks I got the car about 2 months ago and started to make it "safe" by changing all the brake calipers and master since the car has been sitting for about 5 years. Now I want to start driving it and giving it a little OOMPH!!! while still checking out the suspension and things to make it safe

 

Do you live in a state that has strict emissions enforcement?

 

Ya California

 

You really can't do much of anything with a 76 that still needs to pass emissions.
I know it's not what you want to hear, but a 75 or older is emissions exempt. You may want to consider an older car.

 

Ya I know missed it by 1 year. Since I got my car for free from my girlfriend I dont think Im getting rid of it anytime soon and dont have the space for another one or I would build one for me and one for her so thats where I am kinda stuck but thanks for the info

 

I bolted on headers for my 69 and was amazed at the torque gains across the RPM range. Haven't researched it but you might look for headers that provide for maintaining the AIR injectors. They would have to come with a CARB certificate to put on the firewall.

 

Look into emissions compliant parts. For a time, I had to pass Florida emissions. I had emissions compliant Hedmann hedders, high-flow dynomax 3-way cat (I disabled the EGR and the 3-way cat handles the NOx that EGR fixes), emissions compliant cam from Crane (Energizer 272-H10), Edelbrock Performer 2101, tuned carb, good Accell ignition, etc.. You can wake that 'ol L48 up with the right combination of parts and still pass the underhood, undercar and tailpipe tests.

Others in your shoes have done the same.

You can still even go with a better base timing and ignition curve and pass emissions. That is the easiest and cheapest route to go other than swapping in a $40 K&N filter in place of the paper element. That was THE first performance improvement I made back in '97 on my C3. Boy, did THAT get the ball rolling

 

Getting ready to put a set on my stock 69 350/350 hoping for similar results. Glad to hear first hand. Say hello to Krazy Kat for me.

 

Girlfriend gave you a corvette? Put a ring on that finger and who knows what you may find in your driveway.

 

Most cars with this combination would be pretty slow: 350, AFR 180s or 195s, dual plane intake with EGR (Edel 3701, GM 10185063), 1 5/8" headers (see below), decent compression and a cam in the high 210s (Crane, Lunati both sell EO'd cams in this spec and you can spec out a similar roller cam as well and add a few more HP while maintaining low overlap). Mine did 450hp on the engine dyno. 480 tq.

Hedman 68301 and a few more by hedman are legal for 75-79, think it might extend into 80/81 as well but not sure.

 

I have heard how strict California is with emissions, but you asked about cheap power. Simplest and cheapest is the timing - read this;

https://www.corvetteforum.com/forums...long-post.html

It will give you a good place to start. It's darn near free if you can do it yourself. If you still have a stock/factory timing curve, you will notice an improvement.

After that, it's headers/intake as mentioned above, those can still be done fairly inexpensively, and parts are readily available at swap meets, craigslist, ebay, etc.

After intake/headers, you will start getting into the engine and spending more money. OF course, you still need to make sure you won't violate any smog laws, so you will have to know what your local laws allow first.

 

I had the 68301's Jet-Hot coated and installed them on my '80 back around '99. Still have them on the C3 today. That was back when we had emissions in FL. They have a CARB EO # along with the Crane Energizer cam that I ran until 2013. You can have improved performance and still be emissions compliant. Just do your homework and match the parts. You will be pleased. I ran the Dynomax y-pipes and cat until the law was repealed and promptly attached true-duals with H-pipe to the 68301's. Still have the super turbo mufflers on the car from that kit.

 

my guess would be a boring crossover and no more Corvette.

 

REAR END GEARS.

While changing your rear end gears technically isnt 'adding' horsepower, it drastically changes how that power gets applied. You will loose some top end speed, but if you arent a highway driver, you will never notice the difference.

I had a Camaro with a set of 2.88 gears. I could barely break the tires loose. I installed a set of 3.73's and it was like wooooooohoooooo!!!!!

Dollar for dollar, its the cheapest mod with the highest gain you can make.

 

Yes, that would be the first place I'd suggest looking as well. A deeper rear gear will increase torque multiplication at the rear tires across the board. However, if you're after a general purpose performance ratio, and not focused strictly on 1/8 or 1/4 mile ETs, IMHO it's tough to beat a 3.55. In any event, bear in mind the percentage difference between your current gear and the new one in question will directly determine the bang you'll get for this particular buck. For instance, stepping up from a 3.08 to a 3.55 will yield ~15% more torque multiplication while stepping up from a 3.36 to a 3.55 is only worth ~6% more at the same expense. So, do your maths.


Under the hood, assuming a healthy mill, I'd install a performance air filter, and super-tune the ignition system and carb, in that strict order. Upgrading the HEI's innards wouldn't be a bad call. However, I would NOT suggest swapping to a smaller aftermarket carb. They're not the easiest to deal with, but IMHO a well tuned Q-jet is better than any undersized aftermarket carb.


In future, other than headers and freer flowing exhaust system (and perhaps a better intake), I wouldn't bother with much else until you can afford to bump up your L48's meager compression ratio, even if only done by milling your existing heads (assuming they're not cracked). A 3-angle valve job would be worth considering if possible to budget in at this point.


It's easy to over-spend other people's money, but I do hope I've stayed within the more budget minded suggestions.