engine swap
Instructor
Joined: Aug 2009
Posts: 147
Likes: 2
From: Bargo NSW
I would agee with a lot of the other comments made, put an overdrive transmission in. I did this and bought my rpms down from 3500 to 2200 at hwy crusing speed. I would never contimplate swapping out the bb for a sb.
The other thing is as also mentioned is the recouping the cost for the conversion in saved fuel.
I can't speak for everyone here put I'm pretty sure we all drive for fun and not fuel economy this is a hobby about fun... and fun = hp/torque.
The other thing is as also mentioned is the recouping the cost for the conversion in saved fuel.
I can't speak for everyone here put I'm pretty sure we all drive for fun and not fuel economy this is a hobby about fun... and fun = hp/torque.
Burning Brakes
Joined: Sep 2011
Posts: 896
Likes: 7
An intelligent rebuild of your BB with aluminum heads, efficient cam and electronic fuel injection, will be the most cost effective solution. Add a 6sp with a large overdrive and your car will be as efficient as any.
If the next owner wants performance, all he has to do is increase the cubic inches, add some compression and change the cam. It's a win for you and the next owner. If you simply change the motor, your not going to see much of an improved mpg. Your major problem is gearing, and all of the smog related stuff added to the big block from 1973.
A complete conversion to an LS drive train will cost much more than you think. An LS3 conversion on paper will cost about half, of what it actually ends up costing with labor and unexpected parts reqts. LS mpgs mostly come from high gearing, where at cruising speed the motor is turning 1500 rpm. You can do the same thing with what you have and only lose a few mpgs from a limited loss in efficiency. Upgrading what you have will cost $8k-$10k less than a swap factoring labor and unexpected parts swaps. That's a lot of gas, lol.
BBC Conversion Costs (parts only):
Lower end rebuild - $2k
Aluminum heads - $2k
EFI - $3.5k
6sp auto - $4k
LS Swap:
LS3 - $8k
6sp auto - $4k
LS3 computer and wiring harness - $1.5k
new headers or exhaust - $2k
radiator - $.7k
misc - $2.5k
These are just ball park s.w.a.g.s for costs. I didnt mention labor on either swag. Labor on the LS will be more hours and require more talent. Performance will side with BBC and efficiency will side with LS. The last advantage with the BBC upgrade is you can do it in phases. You can do the transmission first and determine the improvements from gearing alone, then do the motor later, or vice versa. You could also leave the egine untouched and add the EFI as a stand alone project. Good luck, I must return to reality, lol.
If the next owner wants performance, all he has to do is increase the cubic inches, add some compression and change the cam. It's a win for you and the next owner. If you simply change the motor, your not going to see much of an improved mpg. Your major problem is gearing, and all of the smog related stuff added to the big block from 1973.
A complete conversion to an LS drive train will cost much more than you think. An LS3 conversion on paper will cost about half, of what it actually ends up costing with labor and unexpected parts reqts. LS mpgs mostly come from high gearing, where at cruising speed the motor is turning 1500 rpm. You can do the same thing with what you have and only lose a few mpgs from a limited loss in efficiency. Upgrading what you have will cost $8k-$10k less than a swap factoring labor and unexpected parts swaps. That's a lot of gas, lol.
BBC Conversion Costs (parts only):
Lower end rebuild - $2k
Aluminum heads - $2k
EFI - $3.5k
6sp auto - $4k
LS Swap:
LS3 - $8k
6sp auto - $4k
LS3 computer and wiring harness - $1.5k
new headers or exhaust - $2k
radiator - $.7k
misc - $2.5k
These are just ball park s.w.a.g.s for costs. I didnt mention labor on either swag. Labor on the LS will be more hours and require more talent. Performance will side with BBC and efficiency will side with LS. The last advantage with the BBC upgrade is you can do it in phases. You can do the transmission first and determine the improvements from gearing alone, then do the motor later, or vice versa. You could also leave the egine untouched and add the EFI as a stand alone project. Good luck, I must return to reality, lol.
Last edited by uxojerry; Jul 20, 2012 at 11:42 PM.
Instructor
Joined: Aug 2011
Posts: 208
Likes: 4
From: Wichita Kansas
If this is an original car, keep looking you will find what you want. Lots of cars out there that you make a swap.
From a math stand point you will never put enough miles on this car to make up for the cost of the swap in fuel savings. Even at $5 a gallon.
Racer
Joined: Jun 2011
Posts: 300
Likes: 3
From: kempton park Gauteng
[
what are you trying to do ??? wreck an icon for fuel economy , most people drive these cars at weekends and as second vehicles . If your using it as a daily driver and worried about the economy , change the gearbox and maybe the diff ratio, or keep it original and buy yourself a Honda to run around in .
wrecking an original big block doesn't make any sense to me .
Get a project vette and play around with that if you have the time and money you want to spend , you wont recover what you spend on the conversion in the fuel you think you are going to save.
QUOTE=scottyp99;1581365062]If you pay the premium for a nice big block car, just to tear it up and put a small block in it, you're an idiot. There are plenty of nice 'vettes out there that already have small block engines, buy one of them. If you don't know what to do with all the money you saved by doing this, just send it to me, I'll put it to good use.
Keep the shiny side up!
Scott[/QUOTE]
what are you trying to do ??? wreck an icon for fuel economy , most people drive these cars at weekends and as second vehicles . If your using it as a daily driver and worried about the economy , change the gearbox and maybe the diff ratio, or keep it original and buy yourself a Honda to run around in .
wrecking an original big block doesn't make any sense to me .
Get a project vette and play around with that if you have the time and money you want to spend , you wont recover what you spend on the conversion in the fuel you think you are going to save.
QUOTE=scottyp99;1581365062]If you pay the premium for a nice big block car, just to tear it up and put a small block in it, you're an idiot. There are plenty of nice 'vettes out there that already have small block engines, buy one of them. If you don't know what to do with all the money you saved by doing this, just send it to me, I'll put it to good use.
Keep the shiny side up!
Scott[/QUOTE]
Advanced
Joined: Jul 2011
Posts: 68
Likes: 0
From: Jacksonville Fl
Is this for real?
How about sell your good condition big block car to someone that wants it--if you got it cheap, the profit to the BB sale will easily pay for a sweet swap car AND a nice portion of the swap engine. I love swap cars--but swap out a common L48 with an LS3. Don't wreck a big block.
These questions suggest a serious need for research--just read through the swaps sections on most any of the forums.
And change your screen name...suggesting something like this...well...it's like mooning the preacher during communion--its hard to go back after stepping on it that badly.
How about sell your good condition big block car to someone that wants it--if you got it cheap, the profit to the BB sale will easily pay for a sweet swap car AND a nice portion of the swap engine. I love swap cars--but swap out a common L48 with an LS3. Don't wreck a big block.
These questions suggest a serious need for research--just read through the swaps sections on most any of the forums.
And change your screen name...suggesting something like this...well...it's like mooning the preacher during communion--its hard to go back after stepping on it that badly.
