Looking for opinions on new Engine

[Otsa580]

I am having some serious thought of making my 69 k/5 blazer into my daily driver. I would like to get some of your thoughts on a new drive train. I would like a fuel injected motor with an overdrive transmission. Some suspension information would be beneficial too!

[5150]

If it's going to be a daily driver then spend the coin on a 5.3/4L60 drivetrain. Then you can go anywhere.

you can typically get the motor for about $600. That typically comes with the starter, alt, brackets, computer, and all harnesses. Also make sure to get all the sensors such as Mass Air Flow and O2's. All of these parts are very high if you don't have them on the motor.

[vtblazer]

Or...if you want to do it on the 'really' cheap, find a 90 4x4 blazer or similar to use the drive train from.

It'll have TBI/700r/241 combo in it.

I picked up a complete running/driving blazer for $500.00 a couple years ago.

Although, if given the option I'd go 6.0/4L80.

[Burt4x4]

I like the looks of the older engine in our rigs so I say after market EFI on top a well built longblock, balanced front to back!
That and a SM465 or NV4500 for hwy 5th gear, rebuild the rest of the drivetrain and yer good for years
Something like this:

[vtblazer]

Originally Posted by Otsa580

I am having some serious thought of making my 69 k/5 blazer into my daily driver. I would like to get some of your thoughts on a new drive train. I would like a fuel injected motor with an overdrive transmission. Some suspension information would be beneficial too!

Burt brings up a good point, what are you going for here?

How are you hoping final fit & finish to be?

What gears are you currently running in your axles?
That will make a difference for transmission option's.

If you go over-drive, you'll want to refer to a gear chart to find out your 'cruise' rpm's on the highway.

[Otsa580]

I agree with you that older engines really fit our rigs. But I would love more mpg.
Right now my blazer has a stock 350 with a 3 speed automatic with 98,000 miles. The dumb thing is that everything works just fine. I will need a new dd soon and thought why not my blazer! But I drive a little to much to stomach 7-9mpg. So I thought why not install a newer 5.3 with an overdrive transmission.

I'm not sure what exactly the axles are because the blazer is at my moms 4hrs away. But they should be stock axles with drum brakes.

I have a while to get the work done so I want to learn as much as I can before I start ripping into it.

[Otsa580]

My original idea when I was in high school was to buy a newer 2 door Tahoe and take the body off and put mine on the frame. But I came to find out that the frame is a little to long. I still like the idea but I know it will never happen that way.

I just want a reliable dd and my blazer hasn't let me down yet.

[vtblazer]

I'm positive your mpg's would increase with a motor & drive-train swap but don't forget the aerodynamics of these old trucks, more like 'LACK OF'.

A lot like pushing a brick down the highway, just sayin', I wouldn't expect miracles or anything but it's gotta help.

[Otsa580]

"A lot like pushing a brick down the highway"

I agree with you on that!

There was a blazer on ebay with a 350 with a 700r4 and he claimed he was getting 10mpg!

[70rs/ss]

A nice 350 with TBI or even TPI (think early 90's camaro's) or even an LT1 with the efi stuff would get you 15-18 mpg pretty easily. I had an LT1 powered Caprice (4800 lb car, so not a truck but weighed the same!) and got 20-22 mpg at 70-80 MPH and the AC blowing ice!! A nice rebuilt Lt1 or TPI 350 with a roller cam, 700r4 trans and the 205 would be a great combo and it'll all fit under the hood. A set of 12 bolt axles (your rear would be fine to stay in there), but find a disk brake front dana 44 with the same gears and you'll be able to stop which is more important than MPG! I'd shoot for a 3.73 gear ratio and keep the tires in the 31" tall range, if you want bigger tires, go to a 4.11 ratio. the 700r4 has a low first gear, so you do not need a low gear ratio to help with off idle acceleration.


The LS engines are a great way to go, but they are spendy if you pay to get the harness and comp stuff done, plus all the upgrades needed to the fuel system, motor mounts, etc. The other really cost effective way to get EFI is to find a Holley Pro jection unit on ebay, they are not state of the art, but function well and will net better mpg, and replace your th350 trans with a 700r4, it'll bolt right in, OD and EFI will give you at least 12-15 MPG if you drive "normal"?

[vtblazer]

Originally Posted by 70rs/ss

and replace your th350 trans with a 700r4, it'll bolt right in

The swap doesn't really qualify for "it'll bolt right in" IMO.

*TH-700R4 is 3"s longer than the TH350 short tail.
*TH700R4's rear mount is 2"s to the rear of that of the TH350 short tail.
*Swapping from a TH350 short tail to a TH700R4 will require shortening the drive-line 3"s as well as moving the transmission mount to accommodate.

[Otsa580]

That sounds like a good idea..........Thanks!

I need to do some work on my heater. The fan would not work last time I tried to use it (I have not looked into it yet) I read the build thread of an installation of a vintage air set up that looked pretty sweet. I do not have an A/C dash and the kit he bought included vents. It looked pretty slick. Although I'm not so sure how well ac would do in a blazer. I usually use the soft top in the summer so that my not be the best idea!

[70rs/ss]

Well, I guess I meant, no special adapters, etc, for instance I just looked at Advanced Adapters site and I need to spend $957 to put an NV4500 into the place where my SM465 is. So a 700r4 bolts in (you need to redrill holes, but it bolts to the bell housing, etc) and if you move the engine forward, you can split the difference in the extra length and shouldn't have to cut a DS down either. So with some extra elbow greese and time a 700r4 is kind of a bolt in?