Enginge/Trans opinions

[Keith6987]

Originally Posted by simicrintz

I agree that an LS engine would be awesome, but there just is something to say about and old rig with an old engine

Very cool.

[Tomo]

My plan for my 70 has been: truck LS/nv4500 (100% has to be a manual) - seems to be the most cost effective way to get fuel injection & over drive. There are a lot of good opinions/options discussed here, definitely has me thinking...

[cleszkie]

Originally Posted by Keith6987

Thank for your input. At one point I had decided to go with a 700r4. I figured the 4:56 would give me the range to go either 35 or 37” tires and keep rpm around 2500 at 65. I don’t have a problem with changing them again to a 4:10 if that will work better with the sm465. I just can’t get the idea of a 4 speed out of my mind. I want a Blazer that looks and feels like an “old” truck. I mostly drive around on the gravel country roads and rarely go over 55 mph. LSs are great I have one in my daily driver, but I want to open the hood and have something that is “somewhat” era correct. Engines are not my strong point , but I have some experience with a basic small block.

When you do your rpm calculations you need to consider that an automatic transmission may be turning a few more hundred rpms than a manual transmission at the same speed driven. Manual transmissions have a solid link to the engine's crankshaft so they turn at the exact same rate as the crank. Automatic transmissions are linked to the crankshaft via torque converter and friction belts that can allow for "slippage". I guess if you have an auto transmission with a positive lock up on the torque converter this slippage can be eliminated. But I thought I would just bring it up.

[Keith6987]

Well , I found a sm465/np205 that was pulled out of a 69 chevy truck. It has all the clutch linkage and cross pivot pieces with it. Cleaning it up should give me something to do while I decide if i'm going to use it. I'm sure I can rebuild them both, I mean I have watched a couple Youtube videos. Ha.

[Keith6987]

Originally Posted by Tomo

My plan for my 70 has been: truck LS/nv4500 (100% has to be a manual) - seems to be the most cost effective way to get fuel injection & over drive. There are a lot of good opinions/options discussed here, definitely has me thinking...

Are you going to use an Advance Adapter to hook up to a NP205?

[Keith6987]

Originally Posted by simicrintz

350 with factory 4 speed manual trans here. I can hold 75 all day long on the freeway

So what tire size and gear do you run? What RPM at 75MPH?

[Tomo]

Originally Posted by Keith6987

Are you going to use an Advance Adapter to hook up to a NP205?

Not 100% on tcase yet. I have a passenger drop np241 out of an 89 k5 that I might use. I will have to replace the input shaft and maybe some other parts? But I bought the 241 when I was a planning for an auto (boring!) it bolts right up to a 4l60e.

This thread came at a perfect time because I’m currently searching for a donor truck. 1999-2007 gm with 5 speed. Yesterday I was reading that the 241 will bolt right up to the nv3500. Just not sure the 4.8/nv3500 is a good fit for a k5 - I’ve posted this question a couple times & get mixed responses. So for now I’m still between 6.0/nv4500 & 4.8/nv3500 (since I want a complete donor truck and don’t want to piece everything together).

[Madkidd007]

May be a little bit late being you’ve bought stuff already, but if truely I decide yet let me list a few things for thought.
1: you said a cruising vehicle, as much as I like manuals they aren’t just cruising transmissions, put an auto in drive and cruise. Also if you’re married and your wife ever needs to drive it for any reason. Can she drive a manual?
2: SM465 ratio is so deep 1st is useless and no overdrive, unless you go with a highway rear gear to drop RPMs.
3: 700r4 & 4l60e both have the same ratio so sbc or LS you can compare trans the same way. 1st gear is a 3.06 ratio vs sm465 2nd 3.58, which you use as first. So not much different starting out except with an auto you can ease into motion with something heavy and not be hard on the clutch. Then again how heavy will you be pulling with a blazer.
* side not you already have a 27 spline np205 which matches a 700/4L60
4: NV4500 is somewhere around 5.4 1st if I remember correctly, similar to the sm464 but with overdrive.

Engine
1epending on where you live and emissions laws old school may be a little more of a pain to meet standards
2: If going old school and wanting to stay correct to the truck, can get pricey if you want all parts period correct. But ultimately the simplest
3:carb vs efi Offroad, normal Offroad no difference. Hard angles and steep grades aren’t affected with fuel injection
4: ls drivetrain is proven and in millions of vehicles since mid 1999 with hundreds of thousands of miles, and if staying with a stock setup you don’t have to worry about maintence anymore than the next guy driving his used Silverado.

Personally if it was me I’d get a used drivetrain from a trailblazer 4wd or Buick rainier awd and have the computer flashed just to delete downstream O2s and anti theft. Keep in mind unlike the trucks they don’t have a TAC module and makes gas pedal compatibility a lot easier. Also all 5.3 trailblazers, rainiers, envoys, and Saab 9-7x used an aluminum block and the 4l60e which you have a transfer case already for.

Now at last if you want a play toy that’s cheap and fun but not to concerned with comfort and cross country reliability/parts availability, extreme cold weather starts and go. Go old school carb with the manual.
By no means am I saying carbs don’t work reliably, just looking at overall conditions and parts availability.

[cleszkie]

Originally Posted by Keith6987

Well , I found a sm465/np205 that was pulled out of a 69 chevy truck. It has all the clutch linkage and cross pivot pieces with it. Cleaning it up should give me something to do while I decide if i'm going to use it. I'm sure I can rebuild them both, I mean I have watched a couple Youtube videos. Ha.

Looks like you got the short throw shifter option there!

[Keith6987]

Originally Posted by cleszkie

Looks like you got the short throw shifter option there!

I don't think the guy would have cut it off if he knew it would be worth $100 some day.

[Keith6987]

Originally Posted by Madkidd007

May be a little bit late being you’ve bought stuff already, but if truely I decide yet let me list a few things for thought.
1: you said a cruising vehicle, as much as I like manuals they aren’t just cruising transmissions, put an auto in drive and cruise. Also if you’re married and your wife ever needs to drive it for any reason. Can she drive a manual?
2: SM465 ratio is so deep 1st is useless and no overdrive, unless you go with a highway rear gear to drop RPMs.
3: 700r4 & 4l60e both have the same ratio so sbc or LS you can compare trans the same way. 1st gear is a 3.06 ratio vs sm465 2nd 3.58, which you use as first. So not much different starting out except with an auto you can ease into motion with something heavy and not be hard on the clutch. Then again how heavy will you be pulling with a blazer.
* side not you already have a 27 spline np205 which matches a 700/4L60
4: NV4500 is somewhere around 5.4 1st if I remember correctly, similar to the sm464 but with overdrive.

Engine
1epending on where you live and emissions laws old school may be a little more of a pain to meet standards
2: If going old school and wanting to stay correct to the truck, can get pricey if you want all parts period correct. But ultimately the simplest
3:carb vs efi Offroad, normal Offroad no difference. Hard angles and steep grades aren’t affected with fuel injection
4: ls drivetrain is proven and in millions of vehicles since mid 1999 with hundreds of thousands of miles, and if staying with a stock setup you don’t have to worry about maintence anymore than the next guy driving his used Silverado.

Personally if it was me I’d get a used drivetrain from a trailblazer 4wd or Buick rainier awd and have the computer flashed just to delete downstream O2s and anti theft. Keep in mind unlike the trucks they don’t have a TAC module and makes gas pedal compatibility a lot easier. Also all 5.3 trailblazers, rainiers, envoys, and Saab 9-7x used an aluminum block and the 4l60e which you have a transfer case already for.

Now at last if you want a play toy that’s cheap and fun but not to concerned with comfort and cross country reliability/parts availability, extreme cold weather starts and go. Go old school carb with the manual.
By no means am I saying carbs don’t work reliably, just looking at overall conditions and parts availability.

Thank you for all the info/advice. I still haven't decided yet. I just bought the sm465 because it was a good deal. I can always resell it. I have the short output shaft kit for the 700r4, I should probably just go that route. It just seems like a lot of hassle and extra $ to use an nv4500 with the np205.

[scott123]

Originally Posted by cleszkie

Looks like you got the short throw shifter option there!

It is funny how in that huge hunk of metal the 'short stick' jumped right out at me too.

The hit wrench is sometimes quicker.

S