What’s up new to the group this is my project car it’s a 1973 Pontiac Grand Prix. I bought it from my girlfriends dad for a grand. I’m currently trying to wrap up the air ride and trying to get this thing to lay a little harder. We named the car Lilith. Also doing a 5.3 swap on it as well and collecting some parts for the motor. 

Look forward to hearing about your progress on the GP

Welcome to FP.

So what is the inspiration/perspiration between the 455-to-LS 5.3 swap besides "because I can"? You looking for better milage, reliablitiy, one fell out of the sky and into my lap? LS motors are great to be sure.

Welcome! Sounds like a cool project. Looking forward to watching your build.

10 hours ago, Frosty said:

Welcome to FP.

So what is the inspiration/perspiration between the 455-to-LS 5.3 swap besides "because I can"? You looking for better milage, reliablitiy, one fell out of the sky and into my lap? LS motors are great to be sure.

It’s literally all those reasons. I live in Colorado Springs at high elevation, I don’t wanna drive this car and have to worry about tuning the carb as I come down, just something I thought about. Then comes gas mileage for the long drive to a car show and use  Sparks in the Ozarks in Noel, MO, that big block is gonna get pretty crappy mileage. The story on the motor I have, I work at a mom and pop dealership as their tech. We had a 09 Tahoe they were in cheap it had 2 collapsed lifter’s and told them let’s just toss a junkyard motor in it and call it a day. I asked my boss what the core charge on the motor, it was $300 bucks. So now I’m doing cam, springs, lifters, dod delete.

7 hours ago, Pontiac 4 Life said:

Welcome! Sounds like a cool project. Looking forward to watching your build.

Thank you

11 hours ago, Ringo64 said:

Look forward to hearing about your progress on the GP

Thank you 

Welcome to FP.  Nice project.  Post lots of pic's as it comes together.

12 hours ago, 719FON said:

It’s literally all those reasons. I live in Colorado Springs at high elevation, I don’t wanna drive this car and have to worry about tuning the carb as I come down, just something I thought about. Then comes gas mileage for the long drive to a car show and use  Sparks in the Ozarks in Noel, MO, that big block is gonna get pretty crappy mileage. The story on the motor I have, I work at a mom and pop dealership as their tech. We had a 09 Tahoe they were in cheap it had 2 collapsed lifter’s and told them let’s just toss a junkyard motor in it and call it a day. I asked my boss what the core charge on the motor, it was $300 bucks. So now I’m doing cam, springs, lifters, dod delete.

I get about 12-14 MPG with my 455/400TH/3.55 erar combination with the top up on the highway. Not bad in my opinion. However, I see your points.

$300 for an LS motor? Where do I sign up? How many miles on the core motor? Do you have to do any machine work or anything preventative?

Sounds like a way cool project. Be sure to keep us abreast of your progress.

Welcome bro, cant wait to see her laid out. I'm a huge fan of all things lowrider!

On 8/11/2020 at 6:28 AM, Frosty said:

I get about 12-14 MPG with my 455/400TH/3.55 erar combination with the top up on the highway. Not bad in my opinion. However, I see your points.

$300 for an LS motor? Where do I sign up? How many miles on the core motor? Do you have to do any machine work or anything preventative?

Sounds like a way cool project. Be sure to keep us abreast of your progress.

Do you really get that off that motor? That’s really not bad at all either. Yeah $300 core. No no machine work, Block looks solid just hoping to cam and springs and call it a day. I wanna say when I pulled it, the Tahoe had like 175k.

Yes I do get that mileage. I record my mileage and gas consumption every time I drive from Michigan to West Virginia for the annual car show in Charleston. It's a combination of expressway and US highways. It's about a 7 hour, 400 miles trip one-way. Drop the top and the mpg drops to around 8 mpg. But hey - it's a convertible - what do you expect?

I know LS motors are stout, but if this was my motor with 175k miles on it, I'd be looking at a set of new bearings, some general block clean up, and perhaps have the crank and bores inspected for wear. Some light port and polish work on the heads (nothing radical - just improve overall flow). Then go with whatever performance improvement parts I had in mind. However, I get that money talks too. It's your wallet at work here. I have not forgotten that. It's merely a suggestion for longevity.