5.3 into 79 trans am
06-02-2009, 04:46 PM
#1
Registered User
Thread Starter
Join Date: Jun 2009
Posts: 3
Likes: 0
Received 0 Likes
on
0 Posts
5.3 into 79 trans am Hi,
I have a 79 trans am with a 400 and 4 speed with 2.73 gears. It doesn't really have the performance or the gas mileage that I need. I use the car as a driver that I can rip down the straights and still turn corners. Instead of rebuilding the 400 and putting a 6 speed with say 3.55 gears I was thinking that I might put a put a 5.3 liter lsx into it.
My car is pretty heavy right now at 3720 with a 200 pound driver. Would a swap to a 5.3 with a t-56 and 3.55 gears be able to run my car into the low 13's and 12's with some minor upgrades and still be able to knock down 25-29 mpg on the highway? I was also thinking that a swap to a 5.3 might shave some weight off of the front of my car?
I currently have a mandrel bent 2.5 inch dual exhaust with a crossover on the car. If I swapped to a 5.3 I would just have to swap my headers and install some oxygen sensors in my exhaust right?
thanks for the help
drew
I have a 79 trans am with a 400 and 4 speed with 2.73 gears. It doesn't really have the performance or the gas mileage that I need. I use the car as a driver that I can rip down the straights and still turn corners. Instead of rebuilding the 400 and putting a 6 speed with say 3.55 gears I was thinking that I might put a put a 5.3 liter lsx into it.
My car is pretty heavy right now at 3720 with a 200 pound driver. Would a swap to a 5.3 with a t-56 and 3.55 gears be able to run my car into the low 13's and 12's with some minor upgrades and still be able to knock down 25-29 mpg on the highway? I was also thinking that a swap to a 5.3 might shave some weight off of the front of my car?
I currently have a mandrel bent 2.5 inch dual exhaust with a crossover on the car. If I swapped to a 5.3 I would just have to swap my headers and install some oxygen sensors in my exhaust right?
thanks for the help
drew
06-03-2009, 01:18 PM
#3
Teching In
Join Date: Dec 2006
Posts: 45
Likes: 0
Received 0 Likes
on
0 Posts
Isn't that 400 in the trans am a 403 olds? A friend of mine has one in a 80ish model cutlass, it's a real torque monster. He does have a custom ground cam in it, and some milling of the heads and flat tops. I like the feel of it. I believe it runs about 12.30 and the 1/4- with a TH350 and the same gear as you.
Why not stick with the 403, put an OD transmission in and fuel inject it?
If you want to go with the 5.3, and t56, that's a good economical combo.
Be ready to learn a lot. I think GMHTP has a few writeups and some moderate 5.3 builds.
I'm sure there are a set of headers made by one of the sponsors that would fit your application as well.
Yes you'll need o2 sensor provisions in the headers. Along with and ls1 or ls6 intake, as I'm not sure that truck intake will clear the hood. Don't forget about the computer and all of the wiring as well.
My brother and I are getting an 88 formula ready for an LS2/4l65 combo- pretty much a stock setup with a little P1SC. It's all in my GTO right now, and FYI I get about 23 MPG on the interstate. It's not nearly that good in town because of the 3800 stall.
sorry to ramble!
Why not stick with the 403, put an OD transmission in and fuel inject it?
If you want to go with the 5.3, and t56, that's a good economical combo.
Be ready to learn a lot. I think GMHTP has a few writeups and some moderate 5.3 builds.
I'm sure there are a set of headers made by one of the sponsors that would fit your application as well.
Yes you'll need o2 sensor provisions in the headers. Along with and ls1 or ls6 intake, as I'm not sure that truck intake will clear the hood. Don't forget about the computer and all of the wiring as well.
My brother and I are getting an 88 formula ready for an LS2/4l65 combo- pretty much a stock setup with a little P1SC. It's all in my GTO right now, and FYI I get about 23 MPG on the interstate. It's not nearly that good in town because of the 3800 stall.
sorry to ramble!
06-03-2009, 04:57 PM
#4
Registered User
Thread Starter
Join Date: Jun 2009
Posts: 3
Likes: 0
Received 0 Likes
on
0 Posts
thanks trans am's came with 400's and 403's. they had a 180 horse 400 and a 220 horse 400. I have the 180 horsepower version that I built from about 4 different cars. I just graduated college so an aluminum engine is way outside my budget. Does anyone have any idea how much a 5.3 weighs with all the parts on it?
