LS semi-swap

[scott123]

I have a high mileage Tahoe. I have a '71 K5 Blazer chassis.

I am going to put the 2001 Tahoe on the 71 chassis. I am going to keep the TH350/NP205 and use the 5.3.

A buddy of mine did one in a 72 2WD. There were some frame mods for the A/C compressor and I think something for the oil pan clearing.

What issues will I run into by using the TH350? ....all other wiring would remain the same.

S

[mongocanfly]

You'll need the spaced flexplate to put a turbo behind a LS..and the t/c bolts need reamed out..other wise ,no issues in connecting the two..
I had to use a vett oil pan on mine to clear the front axle...
Does the Tahoe and blazer wheel base match up?

[scott123]

I have not measured either yet. I'm sure they are close but I will end up cutting the frame.

It is funny, cutting the frame bothers me less than that one wire hanging around that puts the whammy on everything. LOL

The t/c bolts...reamed for what?

[mongocanfly]

Turbo converter bolt patterns don't match LS flex plate..

[mongocanfly]

https://ls1tech.com/forums/conversio...350-5-3-a.html

[jrpontiac]

I hooked up my 5.3 to a th400 last week. I used this flexplate, it was $56 on Amazon. No spacer needed. ATP Automotive Flexplate z-270. Torque conv. Bolts matched up.

[ls1nova71]

Originally Posted by scott123

I have a high mileage Tahoe. I have a '71 K5 Blazer chassis.

I am going to put the 2001 Tahoe on the 71 chassis. I am going to keep the TH350/NP205 and use the 5.3.

A buddy of mine did one in a 72 2WD. There were some frame mods for the A/C compressor and I think something for the oil pan clearing.

What issues will I run into by using the TH350? ....all other wiring would remain the same.

S

You are going to put a 2001 Tahoe body on a 1971 Blazer frame? I have to ask, why? Seems like a big step backwards and a lot of money and work to get there.

[scott123]

Sort of like every other project on here....why? not to smart off but because I want to....

Years back I put a 85 S-10 on a 72 K5 chassis. 383 with 350/205 with 4.11's on 35's. It was a neat truck and a **** load of fun.

It will not be all that much money as far as LS or conversion projects go.

I have every thing here with the exception of the flex plate and motor mounts.

The Tahoe was long paid for...the K-5 chassis has a 4" lift, 4.11 rear ends, with a 350/205 that was driving when I parted it out. The body is already gone to greener pastures.

This would be my first project with a LS motor but since it will land back in its original home it can't be as big a deal as having to work with harnesses...etc..etc..

S

Originally Posted by ls1nova71

You are going to put a 2001 Tahoe body on a 1971 Blazer frame? I have to ask, why? Seems like a big step backwards and a lot of money and work to get there.

[Jstock85]

Hooked up a 4.8 to a th350 this past summer. I used no spacer just the centering ring and yeah you'll need to ream out the flex plate bolt holes about 1/4". I also had to connect a VSS from Dakota digital to the speedo cable so the pcm would know how fast the truck is moving. The trans fluid tube was bit of a problem because of the missing bolt hole. you can get a bracket on amazon cheap that bolts to the back of cylinder head to hold the tube in place. and there is a place on the pass side of the intake to connect the vacuum line to.

Sounds like a lot but everything fell into place one the motor was put in.