Rebuild the L-48 from my Vette or LT1 from 95/6 Caprice 9C1

L-48 has lots of miles on it. Smokes on start up. Uses/burns/leaks oil. Gets 14 mpg around town and 17 on the highway. Have upgraded to Edelbrock intake and carb, headers/dual exhaust, a/c delete, converted to electric fans. Dynoed at the wheels to 185Hp and 249 lb-ft of torque. TH400 trans. Stock rear diff.

LT1 (not the 265) is from a car I picked up for $500. Did not smoke, ran fine, but had busted rear exhaust manifold studs. Decided to strip it down and rebuild. Never got beyond the strip down and cleaning/painting of parts. Been sitting under my bench in pieces for 5 years.

Would like to upgrade the Vette, but the LT1 seems to have been passed over by the LS line of engines so getting parts and info is limited and prices are higher. Plus the accessory drives would need attention.

Was doing some thinking today with a friend who would help with the rebuild/installation of either. Might make more sense to send the LT1 down the road and focus on a good reliable build of the L-48 adding heads and cam. I really want to do FI but systems are EXPENSIVE. TPI??

My goal is at least 300 HP and 20 mpg using the 4l60e that came with the cruiser.

Thoughts?

I'd stick with the L48. Some modern aluminum heads and a cam will really wake it up, and there's nothing cheaper to rebuild than a small block Chevy.

Who's gonna buy an LT1 in pieces? There a market for this sort of thing?

do the l-48/ fix the abysmal compression. decent set of l-98 aluminum heads from a later vette. TBI for fuel injection should run up to about 300 flywheel horse, and be doable for cheaper than I did mine. most of my expense was in the fuel system. bonus for being able to keep accessories, exhaust, and air cleaner from the vette.

Michael

Keep the L48, but bolt vortec heads on, upgrade valve springs with a decent cam, and done, 300hp, 300tq, and you'll knock down 20usmpg with the 4l60e. Keep the carb, its a fun cruiser that never sees winter, fuel injection isnt THAT much better for the amount of work it'll take

Turn both infor scrap. Replace with a 427 and open side pipes then annoy the neighbors. And their neighbors. And their neighbor's neighbors.

If I have to rebuild one of the small blocks the L48 with some good heads would be my choice.

Wally wrote: Turn both infor scrap. Replace with a 427 and open side pipes then annoy the neighbors. And their neighbors. And their neighbor's neighbors.

I like this. Love that number. However, $$$$$$, and I have a DE instructor's salary.

1)sell the L48 and the LT1...

2)swap in a 5.3...

2)profit

or

1)sell L48..

2)swap in vortec 350 long block with HOT cam kit swapped in...

3)profit

Is the LT1 that bad?

Between the two, do a mild vortec head build on the L48, it will easily meet your goals with a quadrajet on top.

What year 'Vette are you working with? I'm all for using the L48. You may need different pistons to get a decent compression ratio depending on the heads. Not a big deal, SBC parts are cheap as mentioned. This also keeps the car "numbers matching". LT1 not worth the hassle. Using the L48 lets you keep all your brackets, accessories, hoses, wiring etc. etc. Easier and cheaper.

Gearheadotaku wrote: What year 'Vette are you working with? I'm all for using the L48. You may need different pistons to get a decent compression ratio depending on the heads. Not a big deal, SBC parts are cheap as mentioned. This also keeps the car "numbers matching". LT1 not worth the hassle. Using the L48 lets you keep all your brackets, accessories, hoses, wiring etc. etc. Easier and cheaper.

+1 this. The LT1 isn't bad in and of itself, it's just that if you're going to use it in this application you have to change a lot of stuff, accessory drives, add a computer and electric fuel pump if you want to keep FI, you have to figure out how to run the optispark, or what to replace it with if you dont. By then you might as well do an LS swap because you are talking about LS swap $. I'm with the collective on this one, do a rebuild of the L48, put some flattop pistons in it and good heads on it, a nice cam and have fun with 300 whp/300tq+ that won't break your bank.

Id run the LT1. If they can get them to run easily in an RX7 you shouldnt have any problems getting them to work in another GM

Use the 4th gen engine harness and PCM and you have a flashable, reliable, abundant, cheap controller.

At 300hp you wouldnt even need to crack open an LT1, do bolt ons and delete emissions stuff and your there, and it will have OE drivability. If you want more, you could do 340whp with a cam only, and a small one at that like a LPE 211/219 that will still drive almost like stock.

You cant say a Gen 1 is any easier to rebuild than a Gen 2 because its all the same, except an LT1 has better internals stock like lightweight mahle pistons, strong crank, and good rods, plus good flowing heads when compared to the OE Gen 1 stuff. You wouldnt have to build an engine, just rebuild one. It already has high compression, and can easily be made higher if you have an aluminum headed engine by swapping to the iron head lt1 head gasket.

You already have a 300hp engine capable of 20mpg, why build one.

Buying new parts for your Gen 1 can easily creep up on price just to equal an Lt1, that money may be better spent on getting the LT1 to work. Example want vortec heads which are a good, you spend about 800 for new ones, so they wont need any refreshing then you immediately have to spend the money to put in screw in studs if you want to run any type of lift (above .480 IIRC) and you're still stuck with an iron head, which equals less compression and more weight.

Lt1 is the bastard child, because everyone defaults to LS Swap it, that means the oe parts are cheap cause no one wants them, why cant you use a 4th gen Fbody accessory drive? LS stuff isnt cheap anymore, Truck intakes are over 100 dollars now, you used to be able to get those for free.

If you don't have the accessory drive, etc with the LT1, rebuild the L48. Is the sump in the same location on the LT1 vs the L48? The LT1 uses a 1-piece rear main seal and will have a different pan and flex plate.

The L48 is your basic all purpose 350 4bbl Chevy. I'll throw a twist in here. If you need to do anything with the existing crank, get a 383 kit for it. I haven't priced it lately, but a 383 stroker rotating assembly is within spitting distance of getting fresh pistons, resized stock rods and a replacement stock crank. One of my customers has a L48 powered '78. Their 350 is very tired and they are shooting for 400 horse. The 383 kit makes that easy.

Edit: Opti makes some strong points for the LT1...

one of my friends swapped a Caprice LT1 into his 86 Camaro.. he probably has $1k into the whole car due to some junkyard scrounging and making stuff work over a period of a couple of months, and it's a civilized beast that knocks down almost 30mpg if he drives it nice.

but i'd still skip it and go to a newer Gen3 engine of some sort just because they are dirt cheap at any junkyard and can be swapped in for minimal cost with a little bit of research, thinking, and elbow grease. i see lower mileage (100k miles) 01-04 4X4 trucks on the local Craigslists all the time for under a couple grand... pull the motor and part out the shell and have a damn near free 5.3 with 100k miles or more of life left in it.. then figure out the wiring and fuel system, scrounge for some of the stuff you need to physically put it in (F body oil pan, Vette accessories, etc), make some mounts, and put that sucker in there... git er dun... then if you do manage to somehow blow up the 5.3, a 6.0 or larger engine is a bolt in affair if you stumble across a good deal on one..

I would go with the LT1 because it's fuel injected already and can make good power with a few bolt-ons. Like Opti said, you should be able to get a ECU and a wiring harness for relatively cheap and some other items. It also bolts into the chassis and your trans as is. A LS swap will make you change the engine mounts and an adapter for the trans.

For 300hp, a good cam and Corvette cylinder heads should get you there.

novaderrik wrote: but i'd still skip it and go to a newer Gen3 engine of some sort just because they are dirt cheap at any junkyard and can be swapped in for minimal cost with a little bit of research, thinking, and elbow grease. i see lower mileage (100k miles) 01-04 4X4 trucks on the local Craigslists all the time for under a couple grand... pull the motor and part out the shell and have a damn near free 5.3 with 100k miles or more of life left in it.. then figure out the wiring and fuel system, scrounge for some of the stuff you need to physically put it in (F body oil pan, Vette accessories, etc), make some mounts, and put that sucker in there... git er dun... then if you do manage to somehow blow up the 5.3, a 6.0 or larger engine is a bolt in affair if you stumble across a good deal on one..

My local craigslist has a lot of LSx motors attached to transmissions with ecu and harness. Usual price is about $2500. I can find blown ones for about $750. Wish I could find a a whole truck for under $4,000. People have caught on and the junk yards are dry. Race-shops and drifters and other hot-rodders has hiked the prices.

I can find a clean running LT1 with everything needed for less than $1,000.

Unfair indeed.

Its been said over and over but easiest and cheapest is rebuild the l48 with vortech heads and decent intake and carb. Then you dont have to buy all the junk to make the lt1 work

Thanks for all the advice. Opti makes some good points, but on a budget the L48 rebuild seems the easiest way to go. Especially considering the Caprice did not have any accessory drive commonality. I like the idea of TBI, but what about TPI? Worth it?

How hard should it be to put the 4l60e behind the L48? I know it's a different length than the TH400 in there, so driveshaft change. Plus trans mount is in different place. Bowtie Overdrives makes a mount for this swap though I could fabricate.

vwcorvette wrote: Thanks for all the advice. Opti makes some good points, but on a budget the L48 rebuild seems the easiest way to go. Especially considering the Caprice did not have any accessory drive commonality. I like the idea of TBI, but what about TPI? Worth it? How hard should it be to put the 4l60e behind the L48? I know it's a different length than the TH400 in there, so driveshaft change. Plus trans mount is in different place. Bowtie Overdrives makes a mount for this swap though I could fabricate.

Tbi and 4l80e go together like peanut butter and jelly. Get the ecm, wiring, and sensors from a 94-95 fullsize 350 truck. Plug and play aftet you hook about 5 wires to the vette harness. Most difficult part of any junkyard efi swap is the fuel system. Im sure theres an easy solution for a c3 vette.

Tbi vs tpi: both work. Tbi will be easier and closer to stock appearing, as well as easily adaptable to an electronic trans. Will also be guaranteed to clear stock vette accessories and hood. Tpi, take a guess. Tpi has better upper end horsepower support. Tbi will be maxed at about 300 crank hp.

Im a huge proponent of tbi for mild cruisers and lower horsepower applications. Just got done swapping one into my 64 elky.

The LT1 offers few advantages over a traditional SBC. The LT1 aluminum head port was only mildly better than the TPI port. The 1994 iron LT1 head was decidedly better, and in fact its what GM directly copied to make the 96-99 Vortec head.

So, the iron-head LT1 is functionally identical to an SBC with vortec heads. IMO, no need to upgrade all of the extra stuff to get LT1 when you could simply upgrade your SBC.

LT1s tend to bring good money for some reason. Sell the LT1 and use the money to upgrade the SBC.

yupididit wrote: Is the LT1 that bad?

It's not BAD, but it's pretty expensive for what you get. You could probably rebuild the L48 for what gaskets to put the LT1 back together will cost.

Mind you, I rather like the LT1. Its downfall is that the SBC does 98% of what the LT1 is for 40-50% of the cost, and the Gen III engines are waaaay better and also cheaper than the LT1. Chevy made forty years worth of SBCs of various flavor, Chevy inundated the world with a flood of Gen III/IV engines, Chevy made a small handful of Corvettes and F-bodies with the LT1. (Okay, and a very small handful of B-bodies when they decided it was cheaper to put iron head LT1s in than certify SBCs for passcar emissions)

Yeah, there's nothing WRONG with an LT1, but there's just better options and availability now. They were the hot ticket until 1998. Think of them as the next evolutionary step of the SBC to get us to the LSx.

For your particular car... I'd put the LT1 back together, sell it, then pop in some flat top pistons in the L48, either some Vortex or L98 heads, a cam and some form of injection (be it holley projection, OE TBI, etc) and call it a day.

Knurled wrote:

yupididit wrote: Is the LT1 that bad?

It's not BAD, but it's pretty expensive for what you get. You could probably rebuild the L48 for what gaskets to put the LT1 back together will cost.

Huh? How are similar quality gaskets any more for an LT1 than a Gen 1 SBC. Its literally the same engine. People are modifying the Gen 1 bowtie block to use them on LT1s, and Gen 1 intakes for LT1 use.

If you are gonna do a crappy rebuild thats of lower quality than a stock LT1, you MIGHT be able to do it cheaper. Most of those cheap stroker kits have cast pistons 5140 rods, E36 M3 cranks that take a ton of machining to fix, and thicker piston rings.

Try and find were someone broke a stock LT1 crank in a non S/c application, and all you have to do is clean it up, you dont have to worry about breaking a cast aftermarket crank or fixing E36 M3ty journals.

Plus they have really nice Mahle hyper pistons with low friction rings, which valve cutouts, so you can run a huge cam and not have to flycut them.

You could get some Aluminum Lt1 heads for almost free assuming you have a caprice and an accessory drive is cheap to. I couldnt sell my accessory bracket for 20 dollars.

The only thing you would have to do is refresh the LT1 (modify it if you want), bolt it in, figure out the electronics, and the cooling system (Lt1 is reverse flow) and your done.

Mine made 308whp through a T56 with just headers, literally stock intake and no tune, just headers, and got 28 mpg on the highway.

When I sold my LT1 it had 184K and it was as strong as the day I got it. It was supercharged and sprayed throughout its life, got cammed at 108K and revved to 7K everyday until it was sold, it embarrased many an LS1, it was rather trouble free and after seeing it get beat on all the time for 8 years and not care, it converted many of my friends into LT1 believers. In fact it outlived every LS or Gen 1 engine in any of my friends performance cars.

Dont buy what you already have.

Opti wrote: Huh? How are similar quality gaskets any more for an LT1 than a Gen 1 SBC. Its literally the same engine.

I think the only gaskets that interchanges with SBC are the oil pan and the oil seal retainer.

We shan't speak of how hideously expensive a timing set is.