Should I swap?

[Tomo]

Before I start please know that I understand this decision is mine but I would like to get feedback from the purists, the swappers and anyone with an opinion to aid in my final decision.

I have a 1970 CST that I bought as a project. I bought it in boxes. Most of the rust repair is done - this is a very very solid blazer for Indiana (spent many years looking before this one came up). I do have all of the original parts (engine, trans, transfer case, gauges, seats, dealer added ac & so on). I also have the protect-o-plate, window sticker, purchase agreement. I am the 3rd owner, the original owner (was given to him as a HS graduation present) sold it to a fellow forum member in 2006 & I bought it in 2016.

The blazer came with a 307, sm465 & a Dana 20 tcase.

On to my question:
In your opinion would it be a horrible idea to do an LS swap on such a vehicle?

Reason I’m considering the swap:
#1 I hope it will be my fair weather daily all summer & fall (my commute is ~20 mins on county roads).
#2 I want to drive it everywhere (vacations, power tour, who knows - everywhere!)
#3 my first car was a less than street friendly 69 chevelle that would be more at home on the strip (gears, suspension, etc). I still have it and 17 years later it hasn’t changed much and I don’t drive it as often as I would like - never can justify making small changes when a full restoration has always been my goal = dreams were too big for my wallet (during HS, college & early in marriage)!!.

The blazer is the priority because it will be more enjoyable for my family. To sum it up - didn’t/don’t drive the chevelle & I want to drive the blazer!!

Think I will regret the swap? Think I will regret the 307?

Hoping to find the direction of this build so I can stop thinking about it!!

[flashed]

Im in to see where you go .But between a 307 and an LS Swap , I vote LS Swap .Or just sell it to me as I want a Blazer .

[Tomo]

Originally Posted by flashed

Im in to see where you go .But between a 307 and an LS Swap , I vote LS Swap .Or just sell it to me as I want a Blazer .

Haha thanks for the feedback but this one isn’t going anywhere! I’ve wanted a 1st gen k5 since I was 10 or so - right after I saw one for the first time.

[rsavage]

An LS swap would make it more driveable., Carbed or FI? Carbed is obviously simpler. Not an inexpensive swap. I started researching what I would need to do an LS in the Blazer I am doing now and I was pretty quickly up to a point where I would never recoup my dollars - mine is just a plain jane K5 but it will be show quality when I am done as are all my classics - I can't help myself. I don't know how insurance is in your state, but classic insurance where I am - Hagerty or American Collector (both of which I've used) limit the type of driving you can do - i.e. car shows, cruises, classic car related. I can't use my cars/trucks for daily driving as I assume it would be cause for them to deny a claim. So that may be something to consider. In your case, you indicate that you intend on keeping it so what you will end up in it doesn't matter. If you want to drive it on long distances, you will probably have to update to an overdrive trans that you can mate with your TC case. Good luck on whatever you decide.

[Tomo]

Originally Posted by rsavage

An LS swap would make it more driveable., Carbed or FI? Carbed is obviously simpler. Not an inexpensive swap. I started researching what I would need to do an LS in the Blazer I am doing now and I was pretty quickly up to a point where I would never recoup my dollars - mine is just a plain jane K5 but it will be show quality when I am done as are all my classics - I can't help myself. I don't know how insurance is in your state, but classic insurance where I am - Hagerty or American Collector (both of which I've used) limit the type of driving you can do - i.e. car shows, cruises, classic car related. I can't use my cars/trucks for daily driving as I assume it would be cause for them to deny a claim. So that may be something to consider. In your case, you indicate that you intend on keeping it so what you will end up in it doesn't matter. If you want to drive it on long distances, you will probably have to update to an overdrive trans that you can mate with your TC case. Good luck on whatever you decide.

Guess I never thought of the possible insurance issue - I appreciate you bringing that up!

If the swap happens I was thinking 5.3 with efi & a nv4500 trans.

Here’s some inspiration from Delmo’s on the type of swap I would like - just like this but medium olive & black top (originals) - already fround the 8” steelies.
https://www.barrett-jackson.com/Even...TOM-4X4-213136

[twp1]

I would go with the LS swap!

[Lieferson]

LS swap. just keep all the factory stuff incase you do decide to go back to stock. everything is reversible if someone REALLY wanted it stock...

[Tomo]

Originally Posted by Lieferson

LS swap. just keep all the factory stuff incase you do decide to go back to stock. everything is reversible if someone REALLY wanted it stock...

Thanks for the feed back!

I agree keeping all the factory stuff is a must - even though storage will be a pain!

I see in your signature line your 71 is your daily, if you don’t mind sharing do you have full coverage insurance? Any insurance issues that are mentioned above?

[A1971Blazer]

If you can afford it...go with the LS swap...my '70 isn't, and will never again be, "original" in any sense of the word....and I'm OK with that....
I'm getting everything together to swap in a 5.7 LS1 from an '02 TransAm...4L60E and 241C transfer case.
I'm going for drivability, reliability, and better economy......performance isn't my main consideration although the LS1 will add a considerable amount above what I have now.
I respect the "purist" mentality..but in my opinion....you just cannot beat modern efi engine technology.....just my 2¢...
Good luck with whatever you decide..and the decision is ultimately yours....

[Tomo]

Originally Posted by A1971Blazer

If you can afford it...go with the LS swap...my '70 isn't, and will never again be, "original" in any sense of the word....and I'm OK with that....
I'm getting everything together to swap in a 5.7 LS1 from an '02 TransAm...4L60E and 241C transfer case.
I'm going for drivability, reliability, and better economy......performance isn't my main consideration although the LS1 will add a considerable amount above what I have now.
I respect the "purist" mentality..but in my opinion....you just cannot beat modern efi engine technology.....just my 2¢...
Good luck with whatever you decide..and the decision is ultimately yours....

Nice! Are you doing a build thread? I picked up a np241 last year - thought it would be a good thing to have if I end up doing the swap.

[A1971Blazer]

Originally Posted by Tomo

Nice! Are you doing a build thread? I picked up a np241 last year - thought it would be a good thing to have if I end up doing the swap.

I haven't started a thread yet....still working on getting my shop addition complete...I do have a few pics of the mock up...using a separate frame..then I'll swap the body onto it when it's complete.

[Tomo]

Originally Posted by A1971Blazer

I haven't started a thread yet....still working on getting my shop addition complete...I do have a few pics of the mock up...using a separate frame..then I'll swap the body onto it when it's complete.
Attachment 1740742

Attachment 1740743

Attachment 1740744

Looks great - what’s your plan for the trans/tcase cross member? Also what motor mounts are you using?

[A1971Blazer]

Originally Posted by Tomo

Looks great - what’s your plan for the trans/tcase cross member? Also what motor mounts are you using?

I'm in the machine shop and fabrication business...I design, machine, and weld all my stuff to be custom fit...
here's a few pics of the cross member motor mount in process

Main cross member weldment


The engine block mounts are billet aluminum...
the center section is a steel sleeve with polyurethane bushings
should help dampen and isolate any vibration
The sleeves were then welded into the "C" notched part of the cross member seen in the first picture


All pieces milled on CNC machine


Bolted to the engine here
there's two additional pieces (not shown) that bolt into the frame rail..
after final engine position is determined

[hemi43]

To be fair, the 5.3 is not an LS engine. Similar, but still not an LS.
Like others have said going with the 5.3 (Vortec) is the way to go. Use the factory EFI with
factory computer or aftermarket computer. Don't put a carb on it.
The best year to use is 2002 because it was the last year that used drive by cable. 2003 and up are OK, but anyone that's used these (me included) hates the pedal response and feel from the drive by wire.

[A1971Blazer]

Originally Posted by hemi43

To be fair, the 5.3 is not an LS engine. Similar, but still not an LS.
Like others have said going with the 5.3 (Vortec) is the way to go. Use the factory EFI with
factory computer or aftermarket computer. Don't put a carb on it.
The best year to use is 2002 because it was the last year that used drive by cable. 2003 and up are OK, but anyone that's used these (me included) hates the pedal response and feel from the drive by wire.

It's just gotten to where everyone uses the term "LS" for that generation....the LS1 was the pioneer and the others were then manufactured using that base...
many variations made and all were designated with an "L"...The Vortec 4800 LR4 (VIN code "V") is a Generation III small block V8 truck engine....The Vortec 5300, or LM7/L59/LM4, is a V8 truck engine...some were cast iron, some were aluminum...The Vortec 6000 is a V8 truck engine LQ4 or LQ9....and the chronology goes on....all all very sound platforms for a various range of engine swaps...

For me what makes the swap combo..is the driveability and reliability....I want to load up someday soon and make a road trip in the K/5....

[A1971Blazer]

For the transmission cross member..I will probably make it from DOM tubing and integrate a skid plate just for the fun of it...
I used to be heavy into off-roading and we built many rigs in my shop...
I like fabricating my own custom stuff...it always fits real nice...

[twp1]

Wow! That looks good!

[A1971Blazer]

Originally Posted by twp1

Wow! That looks good!

Thanks...! I was making good progress on my shop addition then the weather turned cold.....that has to happen before the swap starts...

getting there with the shop...

[hemi43]

Crossmember looks good !!

[Tomo]

I appreciate all the feedback. I’ve decided I’m going to do the swap. Since I want a manual trans I’m gonna start searching for a donor 2000-02 3/4 ton with 6.0 & nv4500. That will only leave me to figure out the passenger drop tcase. Will the length of the np241 be an issue behind the nv4500? Would a 205 a better fit?

This won’t be a fast moving project but I am glad to have the direction nailed down.

-Tom

[hemi43]

Originally Posted by Tomo

I appreciate all the feedback. I’ve decided I’m going to do the swap. Since I want a manual trans I’m gonna start searching for a donor 2000-02 3/4 ton with 6.0 & nv4500. That will only leave me to figure out the passenger drop tcase. Will the length of the np241 be an issue behind the nv4500? Would a 205 a better fit?

This won’t be a fast moving project but I am glad to have the direction nailed down.

-Tom

Why 6.0 ? The 5.3 will have enough power, is way more efficient and has no EGR valve.

[Tomo]

Originally Posted by hemi43

Why 6.0 ? The 5.3 will have enough power, is way more efficient and has no EGR valve.

5.3 is still a possibility. I actually really like the 5.3 - have had 2 trucks with it. But my preference is a manual transmission and that was not an option with the 5.3.

My goal is to buy a complete truck (hopefully wrecked to bring $ down) then swap engine and trans - hoping this will keep me from piecing everything together.

Ive thought about a 4.8 and nv3500 but according to all the “online experts” the nv3500 is fairly weak.