Picked up a 73...now need advice.

[manimal]

Been a while since I had a square, but yesterday I picked up a 1973 Cheyenne Super 20 for $400. Its a big block truck/TH400. The guy I bought it from over heated it, put water back in it and drove some more.....next day it ran, but while driving it, it stopped/died. Thats where it stayed. I was hoping it was a simple fix, but the 454 is seized.
Now on to my questions......I have a 1985 C30 parts truck with a good running 350 that I could swap out...."OR".....I have a 1998 L29 complete from a 98 Suburban 2500, I have ALL accessories,brackets, everything from a transplant.
How I got the L29 was a friend of mine is a mechanic, one of his customers had this Suburban that was making noise like a clattering sound from the engine area, so he went and purchased a take out(COMPLETE, even the harness). Had the truck towed 100 miles to my friend to do a swap. I helped him, and when we got to the torque converter, we noticed the flexplate was BROKEN...hence the noise! We did the swap and I bought the engine we pulled with everything for $150. Im 'assuming' its a good engine.(I will pull pan to inspect though)
So which one do I swap into the 73?

[hatzie]

If the Vortec 454 L29 is in good shape I'd go with that. http://67-72chevytrucks.com/vboard/s...d.php?t=576531
If you need the truck right now go with the 1985 350.

[slotard]

To me it depends on what you'll use it for. If mileage is important I'd go smallblock. If it's more of an around town tow rig I'd go bigblock

I like that combination of ride height and tire size, how big are they? Any rubbing?

[manimal]

I bought it to replace my 92 Silverado and my 84 F250 Diesel. I dont NEED it right away, but I dont want this to be a LOOONNNNGGGG drawn out process either.
I have done "some" research and from what I gather, Howell will be my best bet for a quality harness for the L29. I plan on keeping my TH400 and one day adding a GV as I come across them at times.
So does anyone have any advice on how to run fuel lines? What do I need to keep and what can I get rid of? In Cali, 1975 and older does not require emissions testing....

and to slotard, the rims are 96-97 Ford f2/350 factory Alcoas, tires are 285/75/16's. I dont see any rubbing issues. The ride height may be obscured because it is tied down tight on the trailer.

[manimal]

Well, I disassembled the 454 that came out of the truck, and only about a quart and half came out! It also spun #4 and #6 rod bearings...But the good news is I think the crank will clean up at .010/.010.....

Still waiting for someone to chime in about how they ran fuel lines, and other things I will need to perform the L29 swap.??????

I will tell you my plans include a Suburban/Blazer 31g rear tank(doing away with the saddle tanks). It will be from an 87-91 so it will have baffels. I do not need to smog it, emissions equipment is NOT that inportant,but it does not bother me either..so either way. I wil end up buying a Howell harness I guess.

[mcmlxix]

Get an 87 or newer EFI tank and fuel pump assembly. (I just did this on the Blazer) I believe they run at about 14 psi for TBI motors. If you need more PSI, upgrade to a walbro 225 pump on the factory assembly. I Opted to run Dorman Nylon fuel line for feed and return. I also added an inline fuel filter. Check out my build thread for the part numbers and some pictures.

[manimal]

Well, this body may end up going on a '76 K20 chassis(which use to be mine).....so thats when I will swap in the L29!

[hatzie]

Whole lot easier to run the fuel lines and install the electric fuel pumps with the bed and cab off.

[manimal]

Thats my plan so far. But yesterday I pulled the 350 from my dually and put it into the 73 for the time being so I can drive it. I need to thin the herd!
Today I will remove the new exhaust from the dually , cut and shorten it to fit the 73 then weld it all back up. Should be up and running tomorrow

[manimal]

Well, I got the 350 in and running....to my disappointment, there was about a 1/4" of crank walk and the oil pressure was fluctuating....So I unbolted it today and will be pulling it out tomorrow. I will be putting my L29 back in it. It's an original Big Block truck and I plan on keeping it that way.

I pulled the oil pan off the L29 to inspect the bearings. I pulled 1 rod cap and the bearings are getting down to the copper. So I should probably go ahead and roll in some new rods/mains and do a timing set too.
Looks like I need to get these 2 1973 454s sold so I can order a harness and PCM for the EFI!

[TravisMartin]

You really ought to put a 4L80E in there while you're at it; you already have the computer and harness....

That's what I'm doing on my '78 (the thread hatzie linked above) and it isn't especially difficult.

[manimal]

Got the 350 pulled out today...found an unusual item in the end of the crank too! On the back side of the crank where the big hole is there was a broken thick washer!!!??? So that would be the reason for the excessive crank end play!!! I also measured that from the flexplate to block, .104" difference from all the way forward to all the way back!
So with out dropping pan, Im gonna say the crank thrust is prolly wiped out....all that work for nothin!

[manimal]

here's the washer!

[barry1982]

Hi there, Just a suggestion, Im not very familiar with big blocks, but tinkered alot with small. Instead of installing a PCM etc to run the fuel injected big block, can you not convert the modern engine to use a carb / HEI ? I know Edelbrock makes an intake to convert a vortec 350 into a carb/HEi set up.
Just a thought..... Guess I like the "old school" stuff because I can still fix it at home.

[manimal]

I have actually been constipating that for the past couple of days. I have a 1966 cast iron 396 intake and an HEI distributor.....my question would be, do I have to change the distributor gear?

[RPOZ11]

Good Price on the buy for this truck.
I'm just curious :
Why wouldn't you just rebuild the existing 454 ?
Is it the fuel injection vs Quadrajet that is making you consider that EFI 454?

[barry1982]

Once again.... unfortunately, I have minimal big block experience. I have dropped an HEI from a 78 350 right into a 65 283. The distributor gear was the same. I heard big blocks use the same Dist., but have never tried. One thing that might cause you problems is the intake ports on the heads. the 396 may have had different ports than the 454. (rectangular vs oval)

[manimal]

The reason I ask about the distributor gear is because its a factory roller cam. Also the heads are a lrg oval port design, so the 396 intake will match up pretty nicely.

[manimal]

The existing Big Block needs complete machine work. Bored/honed,crank ground,rods resized, all new hard parts and balancing...then the heads.. This L29 is complete and nice inside.
This is getting to be so frustrating that I am also constipating selling the damn thing!..lol

[barry1982]

I would check just for the heck of it if Edelbrock makes an intake for the newer 454. At least than a guy would know if it's possible to convert to "old school", and if the cam has dist drive gear.

[hatzie]

Edelbrock makes a Performer RPM for the Vortec 7.4L
That and a Quadrajet will work OK with the right size electric fuel pump... I don't believe the BB Vortec motors have provision for a mechanical fuel pump.
The Vortec MPFI would be really nice if you could keep it especially on the 7.4L

[manimal]

I would really like to keep the EFI...but at the moment, I dont have $600 for a harness. Like I said, I need to sell the other 2 454s first.

[manimal]

OK, so let me se if I understand this correctly...
To go carb on the Vortec 7.4, I need a fuel tank and pump from a TBI truck, a fuel pressure regulator with a return, and everything else from the early BBC will bolt up?

....AND.....

To go EFI. same tank, Bigger pump, vette filter/regulator and a $600 harness?

[RPOZ11]

I'm not knowledgable on fuel injection but I'll assume you will need a pressure side of the gas supply and a way to regulate that pressure.
Electrical is not my expertise.
Is it the Fuel Economy and effeciency that you are seeking by trying to install all of this?
I've contemplated some aftermarket electric fuel delivery systems.
I'm wondering if there may be another solution to what you are seeking.
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