Hey guys, My engine is completely disassembled and now I am trying to find out which set of parts can give me the horse power I want in a fair Price. I would love to gain more than 350 hp.

My Engine is the original L-48 with Manual Transmission.

So far i have done a bit of research and looked up some parts from Edelbrock. I was thinking of going all Performer. Meaning that i so far was thinking of buying these Parts:

1. Edelbrock Performer Intake Manifold
2. Edelbrock Performer 600 cfm manual choke Carburetor
3. Edelbrock Performer Cylinder Heads
4. Edelbrock Performer Plus Hydraulic Flat Tappet Cam and Lifter Kit


So far this is what i have thought of. I am also boring the engine out .030" over. Can you guys help me out here buy giving me some advice about this set up?

Will this set up work? Are there more parts that i would need to reach optimum performance with these parts? Would I need a certain type of Piston for this setup? Am I wasting my time with these parts?


Thank You for the help in advance.

 

The only thing I see as a restriction is the carburetor size. Depending on how high you will bring the engine RPM wise I would go for at least a 650 CFM carb.

 

for starters...
what are the casting numbers of your heads?
what type of intake do you have currently?
what type of carb?
any work done to this engine previously?

the cost of boring a block is the same no matter what size you bore it to. and oversized pistons are relatively the same price no matter the size. be sure of what size overbore you want before you do it.


ok, bolt on parts do give more horsepower, but machine work to the block work wonders with the right heads and pistons. my motor is bored .060 over. i have regular old chevy iron 58 cc chamber heads with 1.84"intake and 1.5" exhaust valves (it came out of an 84 caprice but they are commonly called "305 iroc heads"". with my block bored .060" over and the deck height trued and shaved to 9" exact, and forged flat top with two valve reliefs i have 11.75:1 compression. it also has an edlebrock 600 cfm manual choke carb, weiand dual plane aluminum intake (which I hate), a comp cams xe274h (hydraulic flat-tappet) cam, nothing special with the valve train, stock corvette (ram horn style) manifolds and short pipes. all this together gives me a respetive 418 HP and 450 FT/LBs of torque, all of this on a budget (including buying the block) of around $1000.

 

Whether you wish to gain 350 HP or just have 350 HP when you're done is going to make a big difference in which direction to proceed. Also, there's a lot more to designing a build which suits your specific purposes than peak HP numbers alone (something the magazines and TV shows often overlook). Does it need to run on pump gas and/or have decent manners? Do you prefer to emphasize bottom-end torque over top-end power? What type of driving do you mainly do, and do you intend on any particular kind of tracking, and if so what kind? What's your budget, and are you dead set on Edelbrock kit exclusively?

Whatever the answers, given added performance is your aim I'd urge you to look into other cams and more carb, and to not overlook offerings from other makers before committing to purchase. If you can afford them go for 4032 alloy forged pistons. They'er stronger than any cast or hypers and lower expansion than typical forgings.

Yes, the L48 is a low compression mill so you definitely need more CR, but IMCO 11.75:1 on pump gas is a bit much, especially with limited intake duration. It's not the holy grail, but you ought best to take theoretical DCR (dynamic compression ratio) into account when pairing cams and CR. And, keep in mind the better your heads, the less cam required to flow the same amount.

There are many ways to skin this cat, and a good many SB guys here who know more about them than I'll claim. They'll most likely be able to give you all the feedback on this you'll be able to digest, and more, but the more we know the more applicable that info is likely to be. Hope the above helps get the ball rolling...

 

It doesn't have to be Edelbrock per say...This setup is basically a rough draft to get an idea of the type of parts i need. Im open to all of your ideas and advice

 

I know what "shaving the deck" is, but I don't understand 9" Exact??? What is 9"?

 

Factory deck height is supposed to be 9.025" inches but more commonly its 9.025"+. Milling the deck to zero deck height will bring it to 9.000" inches. Better would be to leave .010" for cleanup should it ever need it in the future.

 

Hey guys,

Also, what would be a good set of headers and and exhaust system. I was thinking flowmaster super 40s but I'm not sure....Ideas on this would be greatly appreciated

Thanks

 

you are right, .010" is great for cleanup. my machinist told me that rotating assembly came in at 8.995". may not be .010" but i have some.

 

To each their own but I find flowmaster 40s down right obnoxious for a Corvette. A set of Dynomax/Walker turbo mufflers have a nice throaty sound and won't deafen you while driving. Summit house brand headers fit and work great, just depends on your budget. I'd skip any cam with Edelbrock on it and if your Q-jet is rebuildable use that instead, it will flow up to 750cfm. I'd consider installing a decent set of flat top 2 VR pistons along with 64cc heads to acheive a compression of 10:1. OR if you want more torque, go the 383 route, cost wise they are about the same to rebuild as a 350 with the exception that you need a new crank.

 

wow, I didn't know the Q-Jet could go up to 750 cfm. Thanks, As for the camshaft. What brand would you recommend? I've been looking comp cams since the i posted this. What's your take on them?

 

Its not so much about brand as the build combination, gearing, and what the car is used for. Comp is a big company, some guys won't touch their cams due to the old problems with cams going flat. Crane makes goods cams, Engle, Bullet, Speed Pro, Isky, they all do, just depends. Personally I run an old GM L79 "151" which is the 327-350HP grind that's a good all around cam and I don't have to worry about it wearing out. The engine has 10.25:1 compression and runs very well on pump premium.

 

I have the original Rochester Quadrajet carburetor....I'm thinking of rebuilding that carb instead since I found out it could dish out 750 cfm if I rebuild it
The intake is the original that came with the car. I'm not sure if it's a certain design though.
As far as I know the engine has not been rebuilt.

What do u suggest I could do to the engine?

 

Hey guys,

This car is most likely gonna be an everyday car... I'm not planning on racing or taking it to drags....

However, since I'm rebuilding the engine I want to build it the best I can. I want to give it as much performance as my budget allows me to yet keeping it civilized.

Reason I chose edelbrock at first because I've been to a few car shows, meets, and auction and I noticed the majority of the cars had edelbrock so I assumed it was a reliable company to base my restroration around.

This is my first build which is why I feel a bit overwhelmed right now choosing the right parts so u guys' help is strongly appreciated.

 

Now that we know it's going to be an everyday driver, we need to know what the budget will be. $250, $500, $1000 ????

many people use edlebrock because of price. edlebrock packages there carbs and manifolds and sometimes those with cams and lifter sets. these packages and built and tested to work very well as a package and the simplicity of buying a package proven the work intrigues people. edlebrock gives these packages a horsepower and torque rating so one can chose the perfect package for his/her own needs and budget.

another reason many people buy edlebrock carbs is because they are the simplest carbs to take a apart and clean, and a rebuilt kit (gaskets, needle valves, seats, and filter screens) are around $50 (if i remember correctly). although q-jets are difficult to take apart and rebuild, (and the gaskets kits run more expensive) they provide better economy when running in the primaries and better performance when the secondaries are open.

if you are determined to use your q-jet (and there's nothing wrong with that), I would suggest a dual plane manifold because they have better low-rmp (off-idle) response, more torque and better idle over a single plane manifold.

if a camshaft upgrade is on your lift of parts, i would recommend a comp cam. Not one do they provide a wide veriety of cams to choose from, but they are also well priced with and range of $100-$200 for just a cam, or $300-$500 for a complete package including cam, pushrods, lifters, valve springs and retainer clips.

Sorry I must leave for work, so I must finish this when I come home tonight.

 

My budget is over $1000. Now i would like to keep it under $1500

 

How are you going to do machine work on the block, new pistons, new or rebuilt rods, balancing, bearings, rings, cam&lifters, timing set, oil pump, PLUS spend $1,000 on just heads and stay within your budget?

ON that budget I would suggest a bore of .030" assuming the block is fine, a set of Speed Pro Hyper flat tops, rebuild your rods, and go with a set of Vortec heads and Vortec Performer intake manifold, recurve the distributor, rebuild the Q-jet, a set of Summit house brand headers and dual exhaust.

 

Regardless of what upgrades you decide on, MAKE SURE the first one is the cylinder heads. Given your budget and goals, I would suggest looking in your local salvage yard for a set of vortec cylinder heads. You can probably land a set for a couple of Bens. Add another $100 for a good valve job and you're ready to bolt them on. This will be the best improvement to your performance BY FAR!

Look for these on any chevy/GM truck produced from 1996 up. Make sure and grab the valve covers too - they're the center bolt style.

 

now here is something I haven't heard of.... recurve the distributor...

care to explain what this is?

 

machine work can add up fast. rates differ rom area to area but to give you an idea my local rates are:

acid dip and magnaflux - $54
overbore and honing - $188
deck height shaved - $84
freeze plugs R&I - $42
cam bearing R&I - $20
rotating assembly balanced - $200

so just for machine work in my area is around $550 to $600
if the cost is close to the same in your area, there goes 1/3 to 1/2 of your budget.

make sure you ask the machinist if the block you are using will be worth it to have this done ( mainly that the cylinder walls won't be too thin with an overbore).

whether you decide on vortec heads or older style, or what particular cam you are using, make sure to chose heads, cam and have your block work done before buying aftermarket intake and other non-power adding parts.