So its now about time to update the engine in my 79 Vette. It currently has a mildly built carbureted 350 with Sportsmen II heads and a Hydraulic roller comp cam 224 degrees at .050 backed by a Richmond super T-10 and 3.55 gears.

The car is a part time daily driver (summer months) car that sees some fun time on the track, road course. Reliability and fuel mileage are both very important but also need a little bit more power..

So here is the big question, give the 350 a chance with a rebuild, AFR heads and an aftermarket fuel injection system backed by a TKO 600, or go with a LS engine.

Is an LS really all that, and if so would the price tag be really worth it?

 

Which LS?

My C6's LS2 has great mileage, just about double what I get with my '78 all original 350. And of course 400+ HP is in an entirely different league than the stock 170 on the C3.

 

Just curious: Fuel Injection? I posed the same question to my speed guy and he's not 100% on that being an 'upgrade'. Sure, it helps with the cold running and may smooth things out a bit, but with it comes the fuel pump stuff and a bit more effort in tuning. Of course the mileage thing is a biggie...you said that...

If you really wanted to make "a little bit more power", I'd apply the FI money to a little Vortech supercharger and build the engine you have to suit that widget.

I know that may not suit the "natural power" folks, but after driving supercharged cars and "natural" cars, I'm convinced that a supercharged car is MUCH easier on the drivetrain components because it builds power differently...softer...and can generally build to a higher peak than a "natural" car. Given that the 350 likes to rev, it's actually a pretty cool combination.

Just tossing an option out there. That's all.

 

Wow, Quick to get so responses, thank you.

As far as which LS, I would like something like an LS3 such as the GM performance parts crate engine, but that may be to pricey so I think I would have to settle with a used LS2 or LS1 which I would have to rebuild because I am just to picky to run a used engine.

To be a little bit more specific about how my car performs it runs 13.2 sec at 105 mph in the quarter and current fuel mileage is 13-14 in the city 19-20 highway at 55 mph and 15 mpg at 70 mph. Rear wheel HP on a dyno was 325 hp.

My ultimate goal is low 12 second but get 25 + mpg. Do this on a budget and keep it reliable and streetable.

What I have is really a hodge podge of parts that I have collected over the last 14 years and want to get it all working the way I want.

As far as the supercharger I was thinking about that and did some research on the Procharger superchargers. I really liked what I have found out but from talking to installers it would not be possible on the C3 to run it with A/C a stock frame and stock hood.

I will try to figure out how to load photos to show what it looks like now.

 

http://forums.corvetteforum.com/pict...ctureid=111559

 

http://forums.corvetteforum.com/pict...ctureid=111558

 

What Is your budget?

 

Initially to get started and drivable around 6 to 7 thousand, but being a never ending project there will be later funds to add other stuff.

 

Just drop a built Small Block in it. I'm soooo over the LS swap into old cars thing.

 

LOL.....me personally - I'm torn between the two.....

 

Interesting.

Supercharger money would be a lot more expensive than converting to EFI, and you'd have to get a carburetor to support it.

As for tuning EFI vs carbs, I think they're equally time consuming, with carbs being a whole lot dirtier. I can tune a VE table or MAF transfer function and only get my hands dirty installing my wideband setup.

With a carb, I'm installing the wideband, and disassembling the carburetor at least a handful of times to change jetting.

The initial install cost of EFI is obviously higher on a car that doesn't already have it, of course. But once you've wrapped your head around how EFI works, it actually makes a LOT more sense than a carb.

 

LSx. Can't beat em and you'll be glad you made the change. So much info out there now to make the swap easy.

 

I have a 69 that I love. Trick Flow heads, 383, 6 speed, awesome. I bought a 2005 last November. I have seen the light. Although my 69 still has a little more umph, the 2005 is bone stock and throws me back in the seat nearly as much. Pick up a book on LS motors and you will quickly realize that these new motors have stock heads that flow better than the best worked Gen I SBC heads. I'll never change my 69 because I love the classic sound, but if you're driving it routinely, I say get a LS2/3. You can pick up a low mileage LS2 off eBay for around $6000.00 to your door. I'll bet it keeps up with your current setup. Good luck with whatever you end up doing.

 

LSX and T56 all the way.

 

For the budget you say you have, You should build a nice Gen 1 set up with FI, if your budget was at least twice that, I would say go the LSX route. I have a LS2 with a few go fast parts, it's fast and fun to drive. You could build a nice setup for around 10 grand.


Riggs

 

Depends on the buget, and what your cars value truely is. I've owned a couple late model LS engined cars, and petty amazing, with fuel milage that just shouldn't be happening. Can buy a lot of gas for the $6K conversion costs though. I'd probably stick with a Gen1 engine, and put an o.d. tranny on it. Another option, is World Products makes a Gen1 LS cross breed block that drops right in. All Gen1 mounting down low, and high flow LS on top. Not light as the aluminum LS, but not heavy as a BB either.

 

Thank you everyone for the comments.

My big dilemma is that I know how a 350 works and what its potential is, just not sure of the LS. My only experience of an LS a friends completely stock Z28 with an LS1 and my car on the street is a bit quicker than his.

I guess what I am really getting at is between a 350 with a mild roller cam, AFR heads, Holley fuel injection backed by a TKO 600

VS

A stock LS1 or LS2, T56 with maybe a mild cam.

In terms of best bang for the buck, good performance, reliability and fuel mileage?

 

As already mentioned, the LS is the superior design from the ground up. You do not need to spend the bucks for an LS3, many good Lsx engines can be found for quite a bit less.
One of the biggest reasons these newer performance cars are getting such great gas mileage is the Overdrive transmissions installed in them. Turning only 1600 rpm or so at 65 mph. The FI helps too.
With that said, I personally prefer the old school looks of the gen 1 engine in our older corvettes. I had my 350 done by a reputable shop, turning it into a 383, with a healthy roller cam and some well matched aftermarket heads. It'll match that LS3 hp output and I guarantee it didnt cost anywhere near what it would to swap in an LS engine.
Which leaves us to the o.d. Transmission, I'm sticking with the Muncie for now. But if daily driving your potent beast is what you intend to do, then you are going to have to change out that tranny regardless of what engine choice you make. My engine/ rear gearing/ tire combination is gonna have my engine spinning near 3000 rpm at 65 mph. My fuel economy is going to suck, literally. But it is not to be a dd.
Do some research before you jump. Some good articles on swapping LS engines can be found at Chevy hi performance magazine online. And buying an LS engine is just the tip of the iceberg, as no accessories can be swapped over. Lots to think about.

 

Sounds like you're on the right track, but maybe hold off a bit on the Holley fuel injection, as a well tuned Q-Jet is pretty close. Have a friend with a mostly stock 79' L-82 Muncie 3.70 axle car. Did a Keisler TKO od conversion, and what a difference on the highway. Back to LS. Have a C6 LS7 car, and probably better you don't go for a ride in one of these.

 

People always talk budget, but often forget the other two components of the equation.

Time + Money + Ability/Work = Outcome

How much down time do you want to deal with, and how much proficiency do you have/equipement to accomplish this on your own?

Proficiency + Time are things I think people always forget when they go "I have a 6K to blow". Every LS1 thread I've read I see comments from those doing it like "What budget" or "I don't want to know what I've spent so far". And when you lack tools/proficiency to accomplish the swap that means spending more money to pay someone else in most cases. Especially if you get yourself stuck or into trouble.

If you don't want your car down for to long, then a Crate Engine Gen 1 bolt in job is going to be the fastest most affordable route.

Dollar for Dollar, Gen 1 is still cheaper to modify and buy parts for. LS blocks though are starting to age and prices for them should be coming down and more than likely will continue to trend downwards.

That being said, it's the other way around for HP. Mod for Mod, Gen III block vs Gen I block makes more power.