Is it possible to rebuild an older engine using a block from the early 70s 5.7, get a cam/ lifter/ springs set for TPI, as well as use the heads from a TPI engine.
The block casting is: 3970010 heads casting is:14101083

Yes it will work although the older blocks use a two piece rear crank seal that requires an older style flywheel

Sounds good.
Im just stuck with a decision here.
My reman engine blew and the block cracked, so I have the option to buy a 70's engine that runs but is carb, or I change the internals with a kit, use the heads from the reman engine.
I just dont know what route to take, the harness is out and Im not sure how to wire things up with a carb setup.(gauges, transmission)
Any links to sites with instructions on converting TPI to carb in third gens?

Are you planning to keep the TPI or are you set on a carb swap?

In all honesty, I have all the parts I need for fuel inj except an engine block.
Thing is now I have the engine bay clear and options for something good to go in.
This carbed engine was from a 69 ss Camaro so Im told and has been rebuilt 5years ago for the track.
I took the valve covers and oil pan (changed the 2 rear seals) off and its pretty clean in there for an older engine, I ran this engine in an 83 Regal before I pulled it 2 years ago.
With this engine I have the intake and carb both edelbrock, I wouldnt mind trying carb if it wasnt too complicated other wise I would just build a tpi setup for this block.

Well its dead nuts easy to convert to carb. You'll need a fuel pressure regulator if you run a stock in tank pump or swap to a sump ( factory carb ) style tank and a mech fuel pump with lines. Get an older style big cap HEI distributer. Put IGN 12V+ to it and it will start and run.

True enough thats the easy part, I have a dist as well for it.
The trickey part is getting the gauges working, the speedo, tach, prob need a relay to power on the fans. Whats with the hookup from the harness that connects to the transmission?

You should be able to re use all that stuff from the harness you have. Tach is easy. Theres a pin right beside the power in on the distributer that feeds tach signal out on the big HEi units. Speedo comes out of your trans so that should be easy

Guess I dont have a choice with some connections and can the relay to the fans as well.
I wanted less wires in the engine compartment, would it matter if I cut the wires not needed, like the injectors harness?
Can I use a harness from a carbed setup Camaro/ Firebird that would work?

You can't run the TPI cam & lifters because the old block doesn't have the bosses for the lifter valley spider, and I believe the cam nose is different. You'll have to get some retro roller cam & lifter setup to run a roller setup in an old block.

I was thinking a swap like that for mine as well,but I want to keep my ac,and my electric fans operational without hacking the factory harness,I may want to put the bird back to stock someday.

The TPI (083) heads and EFI manifold will bolt to the older 350 block.
You don't need to use a roller cam in the old block. A mild TPI-EFI friendly flat tappet hyd cam and lifters will work fine.
Summit cam #1102 will work just fine with the stock TPI EFi system.
SUM-k1102 cam and lifter set. 204-214@.050 .420"-.442" 112LSA

The cam is rated at 1500-4000 rpm, isnt there something little more agressive around 5000 rpm tha would work?
Would there not be a clearance problem from the pistons with these heads?

Your stock tpi falls flat on its face around 4000rpm anyways, so that cam would be fine. I hacked into my wiring harness. The only thing I did was buy the Painless wiring fan relay kit. It comes with a temp. switch and all the wiring needed to kick the fans on and off when needed.

im in the process of doing the EXACT build with the same engine block and casting numbers.. the engine is built and is going in to the car this weekend.. pictures to follow later. Although w/ the engine swap i'm also running new autometer gauges for temp oil fuel etc...

Take the cams rated rpm range with a grain of salt. It is very similar to the stock TPI cam. It will give similar performance. You won't notice the difference.
Camming up a otherwise stock TPI motor is a slippery slope. The TPI computer cannot tolerate excessive cam valve overlap without you having to compensate in the chip programing etc.
You asked how to put it back together using a older block to replace the 350TPI block. That's how you do it. If you want to modify the motor, thats a whole other can of worms. TPI motors, by nature are not hi rpm motors and do not respond to haveing a big cam installed. The summit cam is a good flat tappet replacement for the stock OEM hyd roller cam. If you want to enhance/bias the upper part of the motors natural rpm range for a little more top end power (peak hp and rpm), install the cam slightly retarded in a "straight up" position, or 1 to 2deg retarded from straight up and port the cylinder heads to improve the upper end engine rpm breathing. You would have to "degree in the cam" first to determine how much advance it has, then move it from there. It will have 4 to 7deg of advance ground in as it is ground to enhance low end torque. Adjusting the cam's installed position ( advance/retard) is very effective to tuning to engines power band without getting carried away.

Try it.