Hey everyone,

I'm new to the forum so I apologize if this is a duplicate thread, but I am looking to replace the engine in my '75 L-48 Stingray with something a little bit beefier. I have always loved the 454, but I have heard that the L-48 model might not be able to handle the 454. Any suggestions would be awesome!

 

What is your definition of "a little bit beefier"? The easiest route is to find a nice SBC crate motor and drop in. With the added power, you need to make sure your brakes, u-joints, suspension and rearend can handle the extra power. The more HP you put in there, the more critical upgrading these other systems becomes. You can fit a big block in there, but it requires a lot more work (proper accessory pulleys, beefier front springs, exhaust work, etc.).

YearOne and GMPP have good crate options and I'm sure others will make other suggestions. Use the Advanced Search option here on the forum and read away. There is A LOT OF GREAT INFO AND HELP HERE!!!

 

Speed costs. How fast do you want to go?

A GMPP or similar crate engine is the simplest way to go. All your current engine's accessories (brackets, plumbing, exhaust, etc.) will bolt right on and your existing chassis setup will handle the conversion. Just make sure that everything is in good working order. If your cooling system, transmission, etc. are in good condition then you should be fine.

 

I have had a '75 for a long time and I agree, the L-48 really sux. I put quite a bit of effort into the rebuild and mod of mine but if I had to do it over I'd probably get a GMPP crate like the ZZ-383.

 

Don't believe everything you hear.

Why not rebuild your L-48? You'll have more fun than you think you will.

 

Depends on your definition of a little bit beefier. I would suggest to go with a GM SBC crate engine like a ZZ4 or ZZ383 for good performance and limited upgrades/changes required.

However, if you want better performance then go with a large displacement SBC like a 427 or 434.

Ultimately you could go with a BBC like a 454, 496, 502, or even a 572 if you desire.

If you want something different and special you could also go the route of a LS conversion which would give you a modern aluminum engine with modern fuel injection in your C3.

However anything other than a SBC, will require modifications and upgrades to parts and systems as indicated earlier in this thread. The LS conversion is probably the most complex engine swap process.

All can be done, depending on the amount of time and money you want to spend.

 

Thanks for all of the help so far!

I have also looked at the ZZ4 for simplicity in swapping out without needing to upgrade a bunch of other parts (like I would have to with a 454), as for the 427 or 434, are there a lot of extra changes that would need to be made to the chassis, tranny, etc.?

 

The SBC 427 and 434 would be a direct drop in replacement for your existing engine as it is essentially the same dimensions as your stock engine.

You can reuse most of the accessories such as the alternator, power steering, radiator etc. Of course this all depends on how radical of an 427/434 engine you build or have built, the more radical it is the more you will have to upgrade.

You may want to adjust the front springs to lower the front end as the custom SBC will likely be a bit lighter than the original engine as it will likely have aluminum heads and aluminum intake.

To take optimum advantage of the increased horsepower you would likely want to add headers and upgrade to an aftermarket clutch if you have a manual trans.

If you have an automatic trans then you probably will want to have it rebuilt to handle the extra torque. Probably will need a new torque converter as well.

The remainder of the upgrades will all depend on how you drive.

Brakes, rear differential, drive train and suspension upgrades will be dictated by whether or not you will race or track the car.

If you will mainly be using the car on the street then the upgrades will only be needed if you drive the car really hard.

Most of the time if your stock systems are in good condition then they will be fine.

pauldana is building a SBC 427 right now and gkull is a great resource.

 

I have the 4-speed manual, and I just put a brand new clutch in. I don't plan on racing, maybe a drag or two a year, but nothing crazy. As for everyday driving, I don't beat up on it too much but I do want it to pack a bit more punch than the 165hp it has now.

I have started looking more into the 427, and am falling in love with it, but it isn't the easiest to find.

 

Hi golf4life49,

The link below is where I purchased my engine from:

http://www.tristarengines.com/catalo...der-heads.html

I was also considering the Shafiroff Realstreet at the time (see below):

http://www.ultrastreet.net/engines/427_realstreet.php

I also looked at the NYES engines as per the link below.

http://www.nyesautomotive.net/427_550_HP.html

The Tristar Pro Star was the best price and they are good people to work with.

They changed the intake manifold to be one that I selected due to hood clearance concerns, they also used straight plug heads instead of angle plug as per my request so I was guaranteed not to have problems with header interference.

Ultimately, if you can't build your own engine like me then I expect that any of these three builders will provide you what you are after. Hope this helps.

 

If your not into building your own, some arnt, look at cnc-motorsports sbc crate engines.

 

I have a 75, it had the L48, I knew when I purchased the car the engine would be replaced. After exhausting all of my local resources (machine shops/engine builders) It was not going to happen locally where I live.
I purchased my 383 Stroker from Smeding Performance and could not be happier with the experience. I did a lot of research and have my reasons for going with them.I was uneasy doing this at first,(long distance and lots of money) however Smeding made it easy. I am sure it could have been done cheaper had I done it myself, I am very mechanical, but know my limits. I have a solid engine that exceeded my expectations.
I have owned the car for two years and it is finally done after a complete restoration. It has been a long expensive road, I knew that when I got involved with this car. The car is such a pleasure to drive, and knowing it will be reliable makes it that much better.