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Old Feb 7, 2012 | 02:09 PM
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Default New member, L48 questions

My father and I are restoring a 1976 vette that I believe had the L48 engine in it, but next time I'm home I'll have to check and make sure, but I doubt it was an L82.

He is 100% certain he wants a fuel injected crate engine (LS2 probably) so he's giving me the L48 to put in a project car that I'll be buying soon (hopefully a 70-71 Camaro). It's sitting on an engine stand waiting at the moment.

I know these engines are near junk stock, but are easily upgrade able.

I'm looking to get 350+ out of it for relatively cheap and moderately reliably. What is the best way to do this? I've been reading around forums for days and can't find an exact solution to what I need etc. The car will be a street car and will maybe be dragged a few times a year, if that.

Any links to websites to help etc. would be awesome to, thank you.
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Old Feb 7, 2012 | 02:20 PM
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I am not a big engine guy but I think that the heads and cam are what are robbing the HP from these engines.
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Old Feb 7, 2012 | 03:08 PM
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Originally Posted by phalen123
I'm looking to get 350+ out of it for relatively cheap and moderately reliably. What is the best way to do this? I've been reading around forums for days and can't find an exact solution to what I need etc.
You couldn't find any information on how to build a 350 HP 355? Heck, I can think of about 20 active threads right here

As with everything, these discussions best start with a discussion of budget...otherwise the discussion goes off in a million directions at once.

Regardless, building a 350/355 is pretty straightforward and doesn't require any rocket science. You can do a straight overhaul of the L-48 with a better cam and some head work and be in the ballpark of 1 HP/CID.

A little reading is a good place to start:

http://www.amazon.com/Build-Max-Perf...8&sr=8-2-fkmr1

http://www.amazon.com/Rebuild-Small-...8&sr=8-1-fkmr3
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Old Feb 7, 2012 | 03:23 PM
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Originally Posted by billla
You couldn't find any information on how to build a 350 HP 355? Heck, I can think of about 20 active threads right here

As with everything, these discussions best start with a discussion of budget...otherwise the discussion goes off in a million directions at once.

Regardless, building a 350/355 is pretty straightforward and doesn't require any rocket science. You can do a straight overhaul of the L-48 with a better cam and some head work and be in the ballpark of 1 HP/CID.

A little reading is a good place to start:

http://www.amazon.com/Build-Max-Perf...8&sr=8-2-fkmr1

http://www.amazon.com/Rebuild-Small-...8&sr=8-1-fkmr3
It's not that I can't find information, it's just that it's so overwhelming!

I looked up the "small blocks on a budget" instead since I'm working with a small block. I really do need to learn more about engine building and what not though as I'm pretty much clueless.


And with power I'm looking more on the high-end side 350 I guess you could say is the lowest I'd want go if I have to. Less than or equal to 430ish would be perfect, I just don't want it to be slow
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Old Feb 7, 2012 | 04:44 PM
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Originally Posted by phalen123
It's not that I can't find information, it's just that it's so overwhelming!

I looked up the "small blocks on a budget" instead since I'm working with a small block. I really do need to learn more about engine building and what not though as I'm pretty much clueless.


And with power I'm looking more on the high-end side 350 I guess you could say is the lowest I'd want go if I have to. Less than or equal to 430ish would be perfect, I just don't want it to be slow
I totally get being overwhelmed - there's a lot to learn

You're taking the right approach - having a good understanding of the fundamentals is key to understanding guidance you recieve from the shop or others. Too many folks just want someone to tell them what to do, and there are too many folks willing to do just that

I encourage you to read around the forum here and look at some of the build threads. Lots of smart engine folks here; sometimes it gets a little random, but it's all good

As for power, don't get too caught up in HP numbers. In the end, it'll be more about what you can afford than what you want. For all the talk about power, most have never been behind an engine making an honest 1 HP/CID. Also note that the cost goes up geometrically past power targets of about 1 HP/CID or so...something to consider.
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Old Feb 7, 2012 | 05:14 PM
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Originally Posted by billla
I totally get being overwhelmed - there's a lot to learn

You're taking the right approach - having a good understanding of the fundamentals is key to understanding guidance you recieve from the shop or others. Too many folks just want someone to tell them what to do, and there are too many folks willing to do just that

I encourage you to read around the forum here and look at some of the build threads. Lots of smart engine folks here; sometimes it gets a little random, but it's all good

As for power, don't get too caught up in HP numbers. In the end, it'll be more about what you can afford than what you want. For all the talk about power, most have never been behind an engine making an honest 1 HP/CID. Also note that the cost goes up geometrically past power targets of about 1 HP/CID or so...something to consider.
Interesting... and I can't say I have been either, except for a 4.6 mustang making 325ish and my Gti which makes 250ish, but thats a turbo and a boring car, thus the reason I'm getting another project

And yeah I like to learn as a I go, I have way to many practice body panels laying around from when I learned how to do paint/body work.


How expensive are 383 builds on these engines also?
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Old Feb 7, 2012 | 05:45 PM
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Originally Posted by phalen123
How expensive are 383 builds on these engines also?
Sounds like some cool rides.

Generally, a 383 is about a wash with a 355. If your stock crank needs work, it's usually about the same price to get a new cast 383 crank. Many shops don't charge much to clearance for a stroker-clearanced rod as they know exactly where and how much to cut and they just do it as part of the block prep.

You will want to feed those extra cubes, which means we start talking about bigger and better heads...and this is where the money starts getting spent
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Old Feb 8, 2012 | 12:46 AM
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Originally Posted by billla
Sounds like some cool rides.

Generally, a 383 is about a wash with a 355. If your stock crank needs work, it's usually about the same price to get a new cast 383 crank. Many shops don't charge much to clearance for a stroker-clearanced rod as they know exactly where and how much to cut and they just do it as part of the block prep.

You will want to feed those extra cubes, which means we start talking about bigger and better heads...and this is where the money starts getting spent

Interesting

I don't know much, but I read that the cranks in the L48 aren't the best and I'm a "build it to be able to handle double what it'll be running" type of person so I'll probably have the crank worked on.

I really need to get home and rip the engine apart to really know the full condition...
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Old Feb 8, 2012 | 07:27 AM
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If you're planning on putting this engine in a car that you don't yet have, maybe you should wait and see what engine is in the car that you don't have yet. It may be a better starting point. Of course we don't yet know what kind of budget you're working with, but a 70-71 Camaro is going to eat up a good bit of it.
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Old Feb 8, 2012 | 10:11 AM
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As you research your build options and costs of each, I recommend you use two readily available and reliable crate engines for comparison purposes:
  • GM Performance 355 hp ZZ4
  • GM Performance 425 hp ZZ383

Spec out a build engine and add up ALL the costs, time, effort, pros and cons, etc., and compare the numbers to a crate engine like these. Buying a crate engine may be more cost-effective than building your own.

After thorough research, I chose the crate engine route, and I am glad I did. I can easily modify my GMP 350 HO to get over the 400 hp mark with a LT1 cam kit and Comp Cams springs.

Our son and another guy in our car club went the custom build route, and they have at least one problem a year. They have a LOT more money and time in their engines than me. I'm too old and have too many other Corvette projects to be messing with the engine every year. However, that might not be an issue for you.
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Old Feb 8, 2012 | 11:15 AM
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Originally Posted by phalen123
I don't know much, but I read that the cranks in the L48 aren't the best and I'm a "build it to be able to handle double what it'll be running" type of person so I'll probably have the crank worked on.

I really need to get home and rip the engine apart to really know the full condition...
I believe the L-48 cranks are cast (?) - which are fine for around 1 HP/CID+. The crank *will* need work, and you'll find that the cost is about the same as a better quality replacement. Overbuilding costs money - great if you have it, and an all-forged rotating ***'y is the best investment you can make...but bring money

Make SURE you read the teardown walkthrough in the book before you just start tearing stuff apart. Condition inspection during teardown tells you a BUNCH about the engine condition.

Plus, you don't want to start your relationship with the machine shop by making them match rod caps ;-)
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Old Feb 9, 2012 | 10:15 AM
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Phalen,

I have a '76 L-48 too and I am considering freshening the enigne in the next 1-2 years. Based on what I have seen on this forum, a good start to get 300-350hp from the L-48 is to get the engine to breathe better:

Vortec heads
Vortec mainfold
cam upgrade
dual exhaust with headers and x-pipe

From what others have said on this forum, the first three above can be done in the $1000-$1500 range.

Crate engines are tempting too.

Good luck and post what you do.

John
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Old Feb 9, 2012 | 10:25 AM
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Originally Posted by phalen123
My father and I are restoring a 1976 vette that I believe had the L48 engine in it, but next time I'm home I'll have to check and make sure, but I doubt it was an L82.

He is 100% certain he wants a fuel injected crate engine (LS2 probably) so he's giving me the L48 to put in a project car that I'll be buying soon (hopefully a 70-71 Camaro). It's sitting on an engine stand waiting at the moment.

I know these engines are near junk stock, but are easily upgrade able.

I'm looking to get 350+ out of it for relatively cheap and moderately reliably. What is the best way to do this? I've been reading around forums for days and can't find an exact solution to what I need etc. The car will be a street car and will maybe be dragged a few times a year, if that.

Any links to websites to help etc. would be awesome to, thank you.
Those motors are nowhere near JUNK. They last a long time and the small block gen 1 motor is an icon. Now if you simply mean it is down on power that is totally different than junk. With heads, intake, cam, headers and duals it will surprise you. Add flat top pistons and roller everything you can have quite a fun motor. But even in stock form I would never call one junk. Just my 2 cents.
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Old Feb 9, 2012 | 03:56 PM
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Originally Posted by bashcraft
If you're planning on putting this engine in a car that you don't yet have, maybe you should wait and see what engine is in the car that you don't have yet. It may be a better starting point. Of course we don't yet know what kind of budget you're working with, but a 70-71 Camaro is going to eat up a good bit of it.
The one I am currently looking at has a 6 cylinder I believe, but i still need to go look at it, I'm in contact with the sellers son, but not the seller which is making things a wee bit complicated. I don't even know if the thing is an rs! But it seems like a good price so its all good and once I'm back home for good things will be much easier.

And when it comes to budget things get a little complicated...

I'll be doing it the same way I did my previous Camaro, and that is that I'll be working and buying things as I need them. I'll do all the body work, paint, interior electronics etc. on my own while working and hopefully by the time I'm finished with all that I'll have enough to finish the engine and pay for some wheels, tires, clutch and maybe a rear end if it's needed... driveline?

I already have a 4 speed out of a 73? I think camaro that is freshly rebuilt that my dad bought a long time ago and decided he didn't want to use.

So basically my budget is as needed, but as cheaply as possible. This car is definitely going to be more cruising oriented also
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