1973 L48 engine rebuild
#1
Instructor
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1973 L48 engine rebuild
Hi everyone,
I just became the proud of owner of my first Corvette - a 1973 coupe with 79k and all the originals, born 4 years before I was :yesnod:
The L48 engine is in relatively decent shape, probably what's expected for the original after 79k miles. It puts out a hint of blue smoke every once in a while (mostly on warm restarts), and the 190 hp just won't do, so I've decided to give it a go at rebuilding the engine with a little more juice.
I've never done anything under a hood more sophisticated than attaching jumper cables (which scares me) so I want to keep this project modest. I have some pretty experienced helpers available, but I'm looking for opinions on how to proceed with the rebuild. It seems like there are tons of options.
I don't want to remove the engine block, and I would prefer not to mess with the exhaust system (it's new). So I was thinking of changing the cylinder heads and replacing some of the other components. Does anyone have ideas about some relatively basic modifications that could keep the engine healthy and give it more muscle?
I'd like to get around 300 hp, I'd prefer not to go too high compression, and I don't have to pass emissions. I'm hoping to shoot under $1500 for the whole rebuild.
Thanks in advance! Can't wait to get started.
I just became the proud of owner of my first Corvette - a 1973 coupe with 79k and all the originals, born 4 years before I was :yesnod:
The L48 engine is in relatively decent shape, probably what's expected for the original after 79k miles. It puts out a hint of blue smoke every once in a while (mostly on warm restarts), and the 190 hp just won't do, so I've decided to give it a go at rebuilding the engine with a little more juice.
I've never done anything under a hood more sophisticated than attaching jumper cables (which scares me) so I want to keep this project modest. I have some pretty experienced helpers available, but I'm looking for opinions on how to proceed with the rebuild. It seems like there are tons of options.
I don't want to remove the engine block, and I would prefer not to mess with the exhaust system (it's new). So I was thinking of changing the cylinder heads and replacing some of the other components. Does anyone have ideas about some relatively basic modifications that could keep the engine healthy and give it more muscle?
I'd like to get around 300 hp, I'd prefer not to go too high compression, and I don't have to pass emissions. I'm hoping to shoot under $1500 for the whole rebuild.
Thanks in advance! Can't wait to get started.
#4
Melting Slicks
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Re: 1973 L48 engine rebuild (humiliategravity)
You might look into the vortec head conversion kit that scoggin-dickie sells $800 includes heads, intake manifold, rocker arms, bolts and gaskets. All you need is a pair of valve covers. Add a new cam and lifters and you have a total personality change for about a grand. Joe
#5
Waka, Waka, Waka!
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Re: 1973 L48 engine rebuild (humiliategravity)
Thanks... which size Dart Eagles would you recommend?
Obviously these are basic guidlines. People may argue about the exact numbers, but these are pretty good numbers to do basic planning with.
And yea, the Vortec conversion is something you want to look into.
[Modified by Fozzy_Bear, 9:08 PM 5/27/2004]
#6
Le Mans Master
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Re: 1973 L48 engine rebuild (humiliategravity)
SOrry, but I'm gonna be the spoiler. There is NO point bolting a bunch of performance parts to a tired, 80K engine (especially the L48). Kinda like putting lipstick on a pig. Find someone you can trust to pull the engine and do it right!!! :yesnod:
#7
Burning Brakes
Re: 1973 L48 engine rebuild (Fozzy_Bear)
I had the same intention with mine and this is what I came up with this winter; Edelbrock 750cfm carb, performance allu intake, a set of 291 heads, .270,.470 comp cam, and headers all this for under a grand thanks to ebay...........your best bet is to find someone who knows this art inside and out and ask a lot of questions. The combinations are endless. :steering:
#8
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Re: 1973 L48 engine rebuild (Michel B)
I have a 79 L48 app 110 thousand miles I have Trick Flow Twisted wedge G2 Heads,Edelbrock Rpm air gap intake and cam,Holley 670 Street Avenger,1.6 roller rockers,Dynomax headers 2 1/2 dual exhaust with x pipe into Flowmaster 50`s all on the stock block with no problems so it is possible to beaf up the L48.Before starting any work I would suggest doing a compression ck on all cylinders first. Congradulations on your new vette :thumbs:
#10
Melting Slicks
Re: 1973 L48 engine rebuild (humiliategravity)
humiliategravity said: I just became the proud of owner of my first Corvette - a 1973 coupe with 79k and all the originals, born 4 years before I was :yesnod:
I don't want to remove the engine block, and I would prefer not to mess with the exhaust system (it's new).
Follow these steps:
1. Pull hood, have a friend help, or I use the rafters in the garage to hang the hood by looping rope around the hood so I can raise and lower it...that way I can return it to the exact same position as it was originally...mark where the hinges bolt up so you can line it up...use something that you can wash off afterwards.
2. Pull tranny...this is not that difficult, easier with a manual since the body can be removed from the bell housing; but, ebrake cable needs to be disconnected at the Y loop near differential, shift lever and linkage needs to be removed, forward U-Joint needs to be removed and drive shaft moved out of the way, speedo cable, clutch lever (for manual), kickdown lever, vacuum line, and cross member (for auto), then remove tranny using a floor jack or custom tranny jack to lower it.
3. Drain engine coolant, remove fan shroud extension (shroud can stay), fan and extension piece and remove studs if possible (otherwise they may scrape or break the fan shroud), fuel line must be plugged and removed, throttle linkage, clutch idle shaft (manual), vacuum lines, accessories (A/C, alternator, power steering, etc.), unbolt exhaust from the exhaust manifolds, remove distributor (helps to clear the firewall), remove lower bolt on motor mounts & use cherry picker to remove the engine and place on engine stand.
4. Now not only can you rebuild the engine without any worry about messing up the car, you can get into the engine compartment and clean it up and paint it...tie up the wires and hoses properly, etc.
5. If you got this far, then clean everything up, measure everything for wear, replace worn parts with upgrades, and put everything back in the opposite order.
Also, I find video taping the disassembly greatly increases the chance of getting it put back together properly.
#11
Re: 1973 L48 engine rebuild (Rockn-Roll)
Follow these steps...
7. Don't throw a single thing away until you have the rebuilt engine in the car running.
#12
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Re: 1973 L48 engine rebuild (humiliategravity)
Thanks all. Does anyone else vote to replace the entire engine in this thing? Is there any reasonable (affordable) way to test the quality of the block?
#13
Re: 1973 L48 engine rebuild (humiliategravity)
Crate engines are everywhere, and are affordable (relatively). GM crate's are a little high, but they're new and they have a warranty. Sallee Chevrolet makes a 325 hp crate engine, with aluminum heads, for pretty cheap. OOHHH MAN! I think you just got bit by the "while I'm at it bug".....don't worry it's not lethal! I try to get bit at least once a month.
#14
Le Mans Master
Re: 1973 L48 engine rebuild (Rockn-Roll)
(replacing cam and not the bearings is bad :nono:
If you have the thing out and are doing a rebuild anyway, change 'em. If you are doing it in the car, do it and don't be worried.
#15
Re: 1973 L48 engine rebuild (humiliategravity)
Thanks all. Does anyone else vote to replace the entire engine in this thing? Is there any reasonable (affordable) way to test the quality of the block?
"While I was at it" :rolleyes: I changed the steering box , the oil pan gasket, popped on new valve covers and gaskets and a new rear main seal, and now I have NO MORE LEAKS! :party:
I've done a hundred other little things along the way, learned a lot, and had a very enjoyable and satisfying time doing it. I have a good friend who knows lots and helps me when I need it. You will have fun, buy tools, and gain an amazing new confidence that you can do it yourself. This forum is also an ultimate resource, use it often.
Just my .02
-Roy
#16
Drifting
I rebuilt my first engine last year an I agree with Rockn-roll
Pull the engine not a big deal to do, clean, tear it down, measure (take to machine possibly), clean again, rebuild, clean again paint, set her back in and enjoy!!!! Get a book buy David Vizard - how to rebuild a Small block Chevy, take tons of pix and ask tons of questions. You will be proud of the accomplishment, know exactly what you have. And did I say be really proud of what you accomplished?
Good luck!
Pull the engine not a big deal to do, clean, tear it down, measure (take to machine possibly), clean again, rebuild, clean again paint, set her back in and enjoy!!!! Get a book buy David Vizard - how to rebuild a Small block Chevy, take tons of pix and ask tons of questions. You will be proud of the accomplishment, know exactly what you have. And did I say be really proud of what you accomplished?
Good luck!
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(By the way.....I'm usually the one who replies to ancient threads without checking the posted date....LOL)
Thanks Men!