Planning stages

[Mcsjr454]

Starting on the planning stage of ground up rebuild of my 79 k5, and have run into the first of the problems I see. Currently it has 350sb, th400, and np203, D44 front, and 12bolt posi rear, all stock. I intend to swap in an LQ4, 4l80e, and nv241. The problem I see so far is fueling. I'd like to keep a factory style mounted fuel tank and sending unit, (in other words no ugly fuel cell inside the cab) Anyone have any ideas for the fuel system? Also feel free to throw out ideas about other parts and systems as well.

Other details of the planning are:

Stock ride height
31x10.50 All terrains mounted on factory d cut 10" wide rims
Ford Taurus power seats (most comfy seats I have sat in)
3" Cowl hood
Lighted moon visor (aka. cab visor)
GMC Sonoma S-15 brake booster and Master cylinder with anti lock delete valving.
3.42 gears
....this is as far as I have gotten so far on the plans


Daily driver, occasional offroad (nothing more than mud puddles really mostly sight seeing and pulling my bro in law out of holes, occasional utility trailer towing, and even more rarely boat towing (18' bass boat less than 40 miles round trip) and lastly my short disabled mother must be able to get into it (hence factory ride height and 31x10.50 tires) Thanks in advance for any responses as you will really be helping me out to start gathering the right parts.

P.S. I will be linking pics of the all original factory blazer as soon as the weather gets warm enough to grab some good shots. She is a little rusty in the typical places, but some of the vacuum line shots, bracket positioning, and other doodads might help someone.

 

[tRustyK5]

TH400/203 stock in a civi K5? I'd love a pic of that...

Why go as far as an LQ4 swap? A much simpler TBI 350 swap would gain you a ton without half the headaches or cost.

I'm not understanding the Sonoma booster with ABS delete?

*personal opinion*

I never liked Cowl hoods much, the stocker the truck is the less good they look on said truck.

Moon visors...any visor really. Fugly

3.73's would be better.

Rene

 

[Mcsjr454]

I'll get ya a pic as soon as the weather picks up, and I did think about just going TBI, even went as far as scouring the local boneyards for the parts, after careful pricing I was looking at 1400 bucks for used parts, or 2g for the holley or edelbrock kit. Currently I can pick up complete but wrecked trucks with the LQ4 and 4l80e for around 2200 and they have the wiring, computer, trans controller ect, thats the main reason for going with the LQ4.

The Sonoma Booster and master cylinder from 97-2004 have the same mounting as the k5, but are run through the anti lock system, the master cylinder has 3 outputs on it instead of the standard 2. And is already set up for 4 wheel discs. Just have to adjust the rear line pressure for my drums, and eliminate the abs controller. From everything I have read it would have better line pressure but the same fluid volume as the stock unit. the booster is a dual diaphram 10" unit on the Sonoma, so less pedal travel and firmer feel. But please anyone correct me if I am wrong, I have not checked these things physically myself, I am going on heresay as I am just in the planning stages.

The 3.73's I also considered, and would consider again the further this project goes along, but when I plug in the numbers on a few of the gear ratio calulators, I get a 3.42 cruising 70mph at a little over 2200 rpm, being in west virginia with all the uphills, this would let the blazer stay in the sweet spot to maintain 70 uphill unloaded without constantly downshifting. At least that was the plan.

Again thanks guys for reading and thanks for posting, I enjoy seeing the passion and courtesy the members here share with each other.

 

[tRustyK5]

Complete TBI systems regularly sell around here in the $300 range...and it's relatively pain free. LS swaps are a lot more involved and spendy.

Brake booster, I'm still not following the reasoning as the 'K' series boosters have never been known to have issues. Why swap out a booster that works just fine? If you want super brakes find a stock Hydro-boost set-up from a diesel or one ton K truck and use that. I guarantee it'll make the S-dime booster feel weak.

As for gearing, I missed the 4L80e bit earlier. If you're going OD trans definitely go deeper on the gears. 70 mph, 3.42's, 31's in OD will be right around 1850-1900 rpm. 3.73's or 4.10's will be better. The 4L80e is another spendy upgrade I don't see a need for based on your planned use. A 700R-4 would do just fine, and doesn't require a stand alone controller (or complete LQ4 plus complete ECM and stuff)

I'm all for overkill on stuff, but it seems you're adding strength and complexity where you don't need it, and leaving known weak drivetrain parts where you might want to upgrade.

A stockish Blazer doesn't need a LQ4, or a 4L80e...save your money and frustration and think about a TBI350 and 700R-4. Same end result minus some horsepower for pennies on the dollar. Take the money saved and upgrade the diff's. Think about a SF14 rear (6 lug) rear LSD, and the gears to make it work as you want it to.

Rene

 

[shovelbill80]

Complete TBI systems regularly sell around here in the $300 range...and it's relatively pain free. LS swaps are a lot more involved and spendy.

Brake booster, I'm still not following the reasoning as the 'K' series boosters have never been known to have issues. Why swap out a booster that works just fine? If you want super brakes find a stock Hydro-boost set-up from a diesel or one ton K truck and use that. I guarantee it'll make the S-dime booster feel weak.

As for gearing, I missed the 4L80e bit earlier. If you're going OD trans definitely go deeper on the gears. 70 mph, 3.42's, 31's in OD will be right around 1850-1900 rpm. 3.73's or 4.10's will be better. The 4L80e is another spendy upgrade I don't see a need for based on your planned use. A 700R-4 would do just fine, and doesn't require a stand alone controller (or complete LQ4 plus complete ECM and stuff)

I'm all for overkill on stuff, but it seems you're adding strength and complexity where you don't need it, and leaving known weak drivetrain parts where you might want to upgrade.

A stockish Blazer doesn't need a LQ4, or a 4L80e...save your money and frustration and think about a TBI350 and 700R-4. Same end result minus some horsepower for pennies on the dollar. Take the money saved and upgrade the diff's. Think about a SF14 rear (6 lug) rear LSD, and the gears to make it work as you want it to.

Rene

couldn't have said it any better........i'd go with the 241 too

31x10.50 All terrains mounted on factory d cut 10" wide rims

what's a d cut rim? 10"?

 

[Mcsjr454]

d cut rim is the factory rims with the vent holes shaped like the letter D.


Really appreciate you guys input. got me rethinking the pros and cons of each EFI now.
Thanks again.