‘72 engine swap

[Muzzy5.0]

OK, so I’ve recently come back to C10’s and bought a ‘72 long bed with a 307 and 3 on the tree. Long term plan is to replace the 3 speed with a 5 speed. But before that I need to sort the engine.
I like the idea of building the 307 a bit, intake, carb, heads a bit of a cam etc. Nothing too crazy (especially with fuel prices over here ) but ..... there’s a guy got a 350 out of a truck (88 - 95 according to the block numbers apparently). Obviously it needs an intake and carb and a dizzy, am I right in thinking this is a Vortec lump ? Is it any good ? Will it mount up to everything else in the truck ? I guess it will need a mechanical fuel pump too ?
Finding a pair of heads for the 307 is not so easy in the U.K. and getting brand new small chamber heads with small enough valves shipped will be expensive.

Thanks in advance ..

[57taskforce]

88-95 will not be vortec but should have the bosses in the intake valley to install roller lifters. And may already by set up with roller lifters if you are lucky. That block also may or may not be drilled for a mechanical fuel pump but the mounting boss will be there. Vortec heads will bolt up to it no problem and get you 40+ Hp alone. If it needs drilled for the fuel pump that is a really easy thing to do here in the Sates, not sure about across the lake. Congrats on the new truck, we like pictures around here! Welcome to the board.

[geezer#99]

You’ll likely need a flywheel for that one piece rear main seal motor.
Better to look for a pre 1987 motor.

[Muzzy5.0]

This is what I’m wondering, the truck motor is £1300 plus I’ll need all the bits, Hei, intake manifold (I’ve got a carb) etc.
There is another fella got a complete running 350 in his Camaro I can have for £2000, it’s already got some kind of Edelbrock intake, carb etc. Block comes back as an LM1 (C8C). I’m assuming it’s a stock cam.
Better bet ? I’ve got a limited budget so I’ve got to spend wisely but I would like to be able to hop up later ...

[geezer#99]

Limited budget says get the 307 running right. If you buy a carb and intake and headers they’ll all get used on a larger motor in the future.
What does the 307 need now?

[slowcpe]

I'm thinking Vice Grip Garage on Youtube built a 307 with a cam and 305 heads and made pretty decent power for not a lot of money. I have somewhat thought about doing that to my 307.

[Muzzy5.0]

The 307 is bone stock with a shot 2bbl carb. Just ordered a carb rebuild kit just to get the truck so I can drive it about a bit. I’ve had it running by pouring fuel in the top and the engine sounds pretty good for the few seconds it runs at a time.
I’ll have to check out Vice Grip. The only problem I have with building the 307 is the heads. You guys over there can just go to your local junk yard and pull a set of 305 heads for peanuts. Harder to do over here, anybody know what heads I need ? Casting numbers ? Or any affordable aftermarket ones.
My worry is if I change out the intake, carb and headers for now, am I going to actually make it worse until I can afford heads ...

[geezer#99]

Sure! carb, intake and headers will work now and on a future bigger motor. Don’t forget an upgrade to electronic dizzy too.
Info here on what casting numbers your 307 has. Plus more 307 heads with other casting numbers you can use.


https://www.mortec.com/castnum.htm

Needing to keep pouring gas in the carb to keep running shows a fuel pump, tank, or fuel lines problem.
Here’s a dizzy you could use.



https://www.ebay.co.uk/itm/222776746...wAAOSwEOpaSKUZ

[Muzzy5.0]

Yep, I’m liking the HEi dizzy. 👍
I might go with a new intake and headers, I’ve got a 600 Edelbrock carb already.
I need a new fuel pump as I think mine is lunched from dragging all the rust out of the original tank ..... looking for a relocation replacement. Blazer tank in the rear is looking favourite ..

[geezer#99]

Do you know about edelbrock carb pitfalls?
They don’t like more than 5 psi fuel pressure and tend to boil the fuel in the bowls.
You might need a fuel pressure regulator or heat spacer. Not always needed but some things to be aware of.
And 12 volts for the hei. You need to bypass the stock resistance wire.

[Muzzy5.0]

No I didn’t know anything in particular about the Edelbrock. I was probably going to run a 1” spacer anyway. Might price up an air gap manifold .....
Any idea where the resister wire is ? Or what colour I’m looking for ?

Was going to throw up a piccy of the old truck but I don’t appear to be able to, the size it lets you put up is so much smaller than anything I’ve got on here ..

[geezer#99]

The air gap isn’t the best idea. They tend to run too cold. Causes drive ability problems.
You need an intake like a performer rpm. One with a square bore flange. The edelbrock performer rpm isn’t really good on a 307 but it’s the intake you’ll want on a 350. Saves buying 2 intakes. Especially where you live.
Resistor wire is cloth covered. It’s connected to the yellow wire on the positive stud on your coil. You might need to unwrap the tape on the yellow wire back enough to find the junction point.