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Boost HP in 78 C3?

A

acmsal

Guest
What heads, cam, manifold and carb would you folks suggest I use to boost
the HP in my 78 S.A. L48w/auto and ac? It has 72,00 orig. miles and runs
strong, but it's no bullet. I want to try and keep expenses below $2000.
 

Jack

Well-known member
Joined
Dec 27, 2000
Messages
1,825
Location
Florence, SC (Timmonsville SC)
Corvette
71 War Bonnet Yellow VERT 71 BH Blue CPE (SOLD)
who's the wrench?

Is the $2K limit for parts only? Or will your $2K include paying a shop/mechanic ... or will you/your buddies do the wrenching?
JACK:gap
 
A

acmsal

Guest
boost Hp in C3

I'll be doing the work myself and I'm looking to raise the Hp from around 180 to somewhere in the neigborhood of 300. The lower is fine. Also the car is driven in Ca. and I need to keep it smog legal. Thanks for any info you folks can provide.
 

AKRAY4PLAY

Well-known member
Joined
Oct 14, 2001
Messages
584
Location
Wasilla, Alaska, U.S.A.
Corvette
'77 L-82, black on black. Full mod 406 small block
ACMSAL,
as Keith mentioned, it takes money to go fast. going out on a limb, i bet the lower end is about do for a freshening up. being an L-48 lower end, i believe the compression is around 8.2 : 1. generally speaking, from my experience (other guys may have better luck), most of the engines made in the '70's, all makes, are do for a rebuild anywhere from 80,000 to 120,000 miles. if you are looking at sprucing up your ride for a couple grand, you may want to look into a GM performance crate motor. Jim Pace has a 350ci HO listed for $2,139.00. This is a complete motor and i believe it also comes with a warrenty!! it will bolt right in car. it makes about 330hp and actually has a nice power delivery and good idle manners. my roommate installed one in his '83 truck, it runs good and strong.
if you are set on using your current lower end. the new vortec heads work good for more moderate motors and run just over $500 a PAIR. they have the new GM bolt patteren for the intake manifold, 90 degrees to the ground on the center four cylinders instead of 90 degrees to the intake face on the head. i know people that have taken their old manifold and drilled, auggered (forgive my spelling) out, the center holes to accept the new angle. that means you can "theoretically" use any small block chevy intake. as for cam, carb and intakes, edelbrock and holley make good kits for a budget. just a reminder, they engineered their parts to work with other parts THEY make. so you may not get the full benefits if you mix and match brands.
looking at everything; wrench time, down time, guarrenty of finished product, and performance for your buck; get the GM performance motor! check it out, i have hopefully attached the link to the end of my novel. best of luck and fun with it!!
brian

http://www.paceparts.com/
 

AKRAY4PLAY

Well-known member
Joined
Oct 14, 2001
Messages
584
Location
Wasilla, Alaska, U.S.A.
Corvette
'77 L-82, black on black. Full mod 406 small block
Keith,
you bet they are! all the GM performance stuff that is listed on the Jim Pace website or in the catalog, is available at any GM automotive dealer!!! just walk up to the parts counter and say "spank my platinum card, please!" most dealers even have the parts in stock, you can't help but to love the ease of wrenching on chevys. it is almost as easy legos, and the parts are nearly as inter-changable!! as for the after-market valve-ish parts, i like the crower stuff! i got a standard race cam, listed part number in a catalog, from them and it made awesome torque in my 406. i just did not like the way it died after mid-5000rpm. so, i called crower, motor still sitting on dyno, and the tech had no idea how to cam for my engine build. not too surprising, i wasn't that sure myself, hence the power falloff. but he, the tech, did something cool. he gave the phone to old man crower himself!! not bagging on MR. Crower, he is a way cool cat!!:upthumbs i described my situation and build to him. after about 15 seconds of silence, i started getting scared. then the most amazing thing happened, like parting the red sea. he said, "let me look at some experimental cam profiles i was playing with back in the day". he came up with a weird grind that i have never seen, and said "we'll run this!" he turned to the tech, me still listening on the phone, and said rush this over and get it ground for this gentleman please. i was floating on cloud nine, then he said the clinching phrase that won my praise. "THIS CAM IS A SPECIAL GRIND AND WORKED GOOD WITH A VERY SIMILAR ENGINE I BUILT. JUST SEND ME THE CAM YOU HAVE NOW, ONCE YOU GET IT PULLED, AND I WILL ONLY CHARGE YOU THE DIFFERENCE IN PRICE." what a guy, can't say anymore than that!! i have never had such good customer relations as that! the new cam cost me $38.97 extra, and that included shipping. the bonus is the new cam is a better alloy made just for high performance applications. and he shipped the new cam before receiving the old one!!!!!!
ACMSAL, call this guy if you decide to refurbish you L-48. his name is Mike Stark, another very helpfull guy and also way nice. he can supply you with all the parts you need and advise you what to go with. plus he was able to beat summit and jeg's prices for everything i got!! i reccomend mike highly, it was and has been a real pleasure doing business with him. best of luck!!
brian
http://www.cfmperformance.com/
 

1979toy

Well-known member
Joined
Mar 20, 2001
Messages
263
Location
Wichita, KS
Corvette
Red on Red 1979 L-48
I'm about (look around to make sure the wife isn't watching me type this) 1,200 into a top end rebuild on my '79 L48. I did it this way because I have a numbers matching engine. Had it not been I would have grabbed a crate motor and bought warrentied horsepower. If I were to start over again right now I would buy heads rather than having them reworked. I've got 650.00 in an old set of heads. Smarter would have been Vortec heads and intake.
Keep us updated!
 

69MyWay

Well-known member
Joined
Jul 3, 2001
Messages
4,364
Location
Auburndale, Florida
Corvette
1969 Killer Shark
Go for the Edelbrock RPM Performace package. You will come in right around your target goal.

Do the RPM heads, cam, intake, and carb. With 9.5:1, good exhaust and ignition, this motor should crank about 425 ponies.

Too bad you are way out in CA. I have a complete 350 roller block with a schweeeet hydraulic roller cam, Edelbrock heads, 9.6:1 fully balanced and degreed motor, roller rockers, all the go fast street goodies (less than 3K miles) that I would let you have for less than $2K.

In fact, I am dropping the Edelbrock package on my big block. We put the same package together on a friends 89 GMC Jimmy V8 conversion. That was the fastest truck I have ever been in, in my life.

An engine is nothing but an air pump. The more air you can get in, and the better you can get it out the faster you go. The stock motors have terrible heads and intakes. Your year model had low compression and restricted exhaust.

I hear Holley is now making a complete package around $2K including aluminum heads, cam, intake. You might check that out as well.
 

AKRAY4PLAY

Well-known member
Joined
Oct 14, 2001
Messages
584
Location
Wasilla, Alaska, U.S.A.
Corvette
'77 L-82, black on black. Full mod 406 small block
ACMSAL,
If you are a purist for restoration or sell the car to one in the future, you may want to think about this. If you pull and rebuild the motor to completely stock specs, your bluebook goes up instead of down when it is altered. we're not talking major money, just looking from a purist standpoint. But, if you swap motors for a new crate engine, KEEP your old one! That way you will have the best of two worlds. You will have a faster and more enjoyable car for yourself, and still have a matching numbers car for the re-sale market!! i just don't know how you can loose with a crate motor! going that route is the best logic for me, you may disagree and that is fine! After all, it is your Vette and paycheck. I just wish you the best with whatever route you take!
Brian
 

1979toy

Well-known member
Joined
Mar 20, 2001
Messages
263
Location
Wichita, KS
Corvette
Red on Red 1979 L-48
Yes I have done all of my own work minus the head machining for screw in studs and large valves, and I thought about doing that!
Comp XE262 Cam and lifter kit
Cloyes True Roller Timing Chain
Fluiddmpr Harmonic Balancer
Ported heads
2.02 / 1.60 valves
Erson Roller Rockers
Edelbrock Performer Intake
and the Hooker headers and side pipes should go on tonight!:D
 
S

SARGE81

Guest
Boost in HP in a C3

I did a GM 350 H.O. 330HP this past spring in my '81 vette. I kept the original engine incase I wanted to go back to a original setup. For the price and a warranty it was well worth it. You will spend over $2000. by the time you add new accessories, like new waterpump, intake, carb.etc....if you use your stock manifolds (ramhorns) you will have to do a little grinding on them, due to the exhaust ports on "vortec" heads are flush with the head. The manifolds won't fit up tight to the head. Actually the "casting tabs" on the top edge of the exhaust manifolds will contact the valve covers, not allowing the manifold to seat flush. If you look closely at the old style chevy heads the exhaust ports are slightly raised away from the head. If you use headers you will not have to grind anything. Also if you keep your A/C hooked up, you'll need to fabricate a bracket from the back of the compressor to the intake to stabilize it. the rest of the brackets and accessories will bolt right up. Hope this helps you out :) Darryl
 
R

redmist

Guest
I'd based my engine on the Performer SBC RPM package (sans that *^*%*% edelbrock 1407 carb) with 6" rods , zero deck height and some longevity protection.
Now that I have a carb that works it is truly frightening. I think represent a very good bang for the $.
 
B

Bullitt

Guest
Hey Brian, which 350 H.O. crate motor are you refering to? Jim Pace has the H.O. ($2100), but without a carb, distributor, water pump, nor a torsional damper. You also need a flex plate for an auotmatic, which all goes for $3100 from Pace. I think Scoggin-Dickey has about the same prices, too. On another note, whatever happened to RHS? I haven't heard anything from those guys in a couple of years. An old friend of mine, about six years ago, sent off his 396 to them and got back a complete street monster. I haven't seen that dude in awhile, either. --Bullitt
 

AKRAY4PLAY

Well-known member
Joined
Oct 14, 2001
Messages
584
Location
Wasilla, Alaska, U.S.A.
Corvette
'77 L-82, black on black. Full mod 406 small block
Bullitt and Acmsal,
sorry guys i was mistaken eariler about the status of the jim pace 330hp small block. Bullitt is right and i am wrong, it is not a complete motor! but, from my researching i think it will still fit Acmsal's needs. i still need to make a couple of calls, but i am thinking that you will be able to reuse your balancer, distributer, exhaust and intake. i am pretty sure you will, but not 100%, but i will find out soon. you will need a new style flexplate, $40, to fit the onepiece rear main seal crank, which is far superior to the two piece you currently have. no more oil leaks! the power will be down from 330 if you use the stock L-48 intake, guessing around 290hp-300hp. i know it sounds hokey with a new motor, but re-using some of the old parts is OK. dampers, intakes and exhaust manifolds don't wear out. the distributer most likely will require some attension. i look at it like this, if you re-use your old lower end, you will be re-using the same parts you need to complete the crate motor. so, it is money that you would have to spend anyway. now you see how easy it is to spend far more than you originally budgeted. with getting the items you need, flex plate and say new intake, re-using your other stuff and rebuilding your distributer, it is very possible to get 300hp for about $2500. still not a bad investment, and a great warrenty to boot!!
as for the rest you guys looking into wicked crate motors, try these guys out. i have never done business with them, but heard very good things from everyone that has. enjoy, and i will do some research in the mean time. big block fans, please be careful of your wallet when you see the 540. massive power, check the numbers! it might be just what a couple of you are looking for, i was very tempted, VERY!! brian
http://www.speedomotive.com/
 

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