1970 4x4 revival, LS questions should I go 5.3 or 6.0??

[1970BLZCST]

I'm getting ready to start my frame off revival of the 70 CST, its got a built 1968 327 in it now with a 4 speed and Dana 20, I bought this rig from a good friend and have never driven it, he started the tear down and then lost intrest and his job making the rebuild impossibile for him, ok I actually traded a 4 wheeler for it........back to my question this rig will be a weekend road driver only, not a mud truck I have available both 5.3 and 6.0's with 4L60E's attached to them, the 5.3 is 500 less than the 6.0, so for those of you who have done it what are the pros and cons of these engines and which one will work best for my needs, I'm planning on using the stock axels and would also need to find a transfer case to mate up with the 4L60.

[72BlckButy]

Check out firebirdjones' thread here:

http://67-72chevytrucks.com/vboard/s...d.php?t=495753

The pics were reposted on the 2nd page and will be updated on the first. He installed a 6.0 and loves it.

[1970BLZCST]

Wow thanks for that link, great info and havent found that link in searches. I appreciate the help

[Firebirdjones]

Thank Nate, he made me aware of this as I have finished a 6.0 swap with a 4L60E in mine.

As far as the 5.3 or the 6.0, it's up to the individual. The 5.3's are easier to find and are obviously priced cheaper.

For a fun truck, weekend toy, even a daily driver with decent performance, maybe even slightly better gas mileage over the 6.0, the 5.3 looks pretty good. Nothing wrong with those engines. They are available in both an aluminum block and a cast iron block. I think they are factory rated around the 300-320 HP mark depending on year.

I chose the 6.0 for a few reasons. The sheer weight of the truck at 4,650 lbs. (scaled it) made me lean towards an engine that produced more torque. I also like the 4" bore because it opens up my cylinder head options later down the road. 6.0's are made in cast iron and aluminum blocks, although the cast iron is easier to find.
I prefer the cast iron for it's ease of rebuilding (boring to be more specific). The aluminum sleeved blocks generally only accept a hone of .005-.010 and resleeving is a very expensive alternative. So I kept all that in mind for later down the road (Been through this with our LS1 camaro's)
Another reason, and this is just me, but I really didn't want to put a 5.3 in a blazer that originally had a 5.7. I felt with all that work I wanted a slight increase in displacement, 355vs364 is a rather small jump, but the performance difference is night and day.

After some extensive tuning, switching to SD (no more MAF), with 3.07 gears currently and running 33" tires I'm getting 17 mpg around town and a best of 22 mpg highway. I average 16/20 regularly though.

I don't think you could go wrong with a 5.3. These 4.8-5.3-5.7-6.0 LS engines with their 15 degree heads make silly power for their size.

[1970BLZCST]

Thanks guys I appreciate the help, I've located a 6.0 complete package for the same price as a 5.3 so I'm going to pull the trigger on it! What is involved with doing away with MAF? is yours cable or drive by wire?

[Firebirdjones]

Mine is a drive by wire. If that's what you wind up with, make sure you also get the gas pedal as well as the little control box. That control box alone is about $500 if you have to buy one.

Getting rid of the MAF is a tuning option. The MAF is basically a fuel control device that senses incoming air. Without it you basically run the engine in Speed Density and it uses the VE tables exclusively according to what AFR you want to run.

The MAF is also a very sensitive device, with a small heated wire. If that gets dirty it skews the readings and causes lean or rich conditions, eratic idle, poor performance etc. and they slowly degrade over time..I also view it as a restriction in the air flow. Although they will generally support about 450 hp before that happens. They can also fail without warning as with any electronic device.
Another advantage to removing it is when doing these retro swaps into older vehicles, it gives you more room to run an air intake system when things are tight. In the Blazers, you have plenty though.
I like to also think of it as one more expensive device I don't have to buy. For some reason, GM is the only manufacture I'm aware of that still uses an MAF. You don't see them on Chrysler and Ford products.

By removing it, it's also one less fuel table that you have to worry about dialing in when tuning.

I have always tuned our 4th gen camaro's and removed the MAF's. I've gotten a slight gain in RWHP but the main reason (other than what I mentioned) is that I really like the snappy throttle response when these engines are in SD mode, there is no delay.

The only real obstacle to watch for is the intake air temp (IAT). Starting in about 2003 (maybe sooner on the truck MAF's) the IAT was incorporated into the MAF. The IAT is something that should stay. So in order to remove the MAF you'll need an IAT relocation kit. Basically a wire that plugs in and runs over to a small IAT sensor. This sensor can be located anywhere in the air intake track. Simply drill a hole and it pushes into a robber grommet.

I forgot to mention another good reason for the 6.0. I do a fair amount of mild towing with mine, a small 12' utility trailer as well as a short camper. Living in a mountain terrain type environment, the extra power comes in handy. You'll like that 6.0

[72BlckButy]

Couldn't ask for better info... nice work!

[1970BLZCST]

I've been bitten by the LS bug! My new to me 2004 6.0 4l60E with 59,500 from a Yukon Denali delivereed yesterday, time to start shopping for crossmember/mounts, and fuel goodies.

[Firebirdjones]

That's a nice Christmas present. Think it'll fit under the tree??

[SamMargritz00]

i did this kind of swap and i LOVE it. modern ride with classic look!

[Firebirdjones]

Originally Posted by 1970BLZCST

I've been bitten by the LS bug! My new to me 2004 6.0 4l60E with 59,500 from a Yukon Denali delivereed yesterday, time to start shopping for crossmember/mounts, and fuel goodies.

Just curious, did you go through Spaulding? Just guessing since you live up in the Washington/Oregon area.

[1970BLZCST]

i used LKQ, they wanted to know my price range, how many miles i wanted to stay around and then went to auction and bought what i wanted and gave me the complete assembly with a 6 month warrenty, I paid 1800 for the assembly and i get t0 go pick out the silverado seats of my choice. I couldnt have asked for a better deal

[Firebirdjones]

Originally Posted by 1970BLZCST

i used LKQ, they wanted to know my price range, how many miles i wanted to stay around and then went to auction and bought what i wanted and gave me the complete assembly with a 6 month warrenty, I paid 1800 for the assembly and i get t0 go pick out the silverado seats of my choice. I couldnt have asked for a better deal

Sounds like a great deal. I used LKQ too. I got the 6.0 with a 4L80E with 80,000 miles complete with everything for $2,000. I ended up spending extra and building a 4L60E for my swap though. The 80 sits here.

Glad to hear it worked out. You'll love it.

[1970BLZCST]

I still need to go pick out the seats I want and also grab a drive by wire accelerator pedal and balck box, they forgot to pull it out of the Yukon but said i could come by and get one anytime i wanted.