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I bought what I thought was a 350 from a salvage yard, but it turned out to be a 307. Ive read some good articles on the 307 so I decided to continue my rebuild. I have bought an Edelbrock Performer Plus cam and lifter kit (idle-5500rpm) and I'm going to buy an Edelbrock performer intake. I need any help/tips I can get on parts or ways to rebuild this motor.
 

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307's are by nature ... not a performance engine. They are General Motors attempt to get by the smog laws of the day ... and a 307 is just a 283 with a 327 crankshaft :embarrass

I would find a 350 ... to spend my $$$ on ...
 

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If you plan to keep the 307 I admire you, since it`s not a run of the mill 350.
I would check the pistons, if they are factory pistons try your hardest to keep them, as all the aftermarket pistons have .020 off the tops that kill the compression and quench, the factory flat top was the ticket, since the only piston you can get with the correct compression height is the forged piston, and since a 307 is a uncommon build, they cost over $400.
I would use heads off a 305, the 416 or 601 casting head will work well and keep the compression ratio within a respectable ratio, a light bowl port job would be of help also. The edelbrock cam will give it great low end power, make sure you add a double roller timing chain.
The 307 is a small block chevy, and it`ll respond to mods just like the other small blocks will. If you want more cubes, take the 307 crank and slap it in a 350 block, you`ll have a 327, just use 327 pistons.
 

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I'd go back and get a 350.

Remember it is a 307, and parts such as cam will seem to be too big compared to a 350. 43 cubes = about 10-12* less cam duration needed for the same power band. Performer Plus cam might be too much for a 307 street engine. I recommend about 208*

Ditto on inductions.
Most aftermarket intakes will have ports larger than the gasket surface of the head.
 

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I really cant tell but did you measure the bore??? that crank looks like a 350.. Look at the middle counter weight and see if the last 3 numbers on the part number is 442..


bigdome16 said:
I bought what I thought was a 350 from a salvage yard, but it turned out to be a 307. Ive read some good articles on the 307 so I decided to continue my rebuild. I have bought an Edelbrock Performer Plus cam and lifter kit (idle-5500rpm) and I'm going to buy an Edelbrock performer intake. I need any help/tips I can get on parts or ways to rebuild this motor.
 

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Discussion Starter #8
DoubleVision said:
If you plan to keep the 307 I admire you, since it`s not a run of the mill 350.
I would check the pistons, if they are factory pistons try your hardest to keep them, as all the aftermarket pistons have .020 off the tops that kill the compression and quench, the factory flat top was the ticket, since the only piston you can get with the correct compression height is the forged piston, and since a 307 is a uncommon build, they cost over $400.
I would use heads off a 305, the 416 or 601 casting head will work well and keep the compression ratio within a respectable ratio, a light bowl port job would be of help also. The edelbrock cam will give it great low end power, make sure you add a double roller timing chain.
The 307 is a small block chevy, and it`ll respond to mods just like the other small blocks will. If you want more cubes, take the 307 crank and slap it in a 350 block, you`ll have a 327, just use 327 pistons.
about the heads, they came with a set of good, well i dont know if thats the word, 882s. i hear those would be alright heads for my setup, but i know for a fact that they overheat and are known to crack...do you think it would be bad or what on my project?
 

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xntrik said:
The pictures will not enlarge. The distance between the bores looks too narrow to be a 307.

Aren't the crankshaft flanges different shapes on 307 and a 350 ?

you have 2 threads going for this engine.

http://www.hotrodders.com/forum/chevy-307-rebuild-106669.html#post748508

Hey Buddy, You have a 350 engine in that picture. Look at the crank flange, it is either a 305 or a 350, and the bore looks like a 350. You need to slap a ruler on the bore OR run a numbers check on the block. 350s are 4.00 bore.

edited= 305 is 3.736 bore,,,, 307 is 3.875 bore. And that is NOT a 307 crankshaft and the metal between the bores is not wide enough for a 305 which is 1/2 inch wider than a 350.


http://www.carcraft.com/techfaq/116_9906_guide/index1.html
 

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Looked at the pictures. That's definitely not a 305, because 305's came with dish pistons. The damper looks like the one off of my 307. If I'm not mistaking most 350s came with dish pistons after `71, could be rebuilt. 4" bore=350, 3.875=307. Don't keep us in suspense.
Also, 882s have too big of a combustion chamber for a flat top 307. You're compression would be 8to1 at best.
 

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Discussion Starter #11
alright, i got a chance to measure the bore on the SUPPOSED 307 motor of mine. the bore measures a perfect 4.001 inches. im pretty confused though because the engine casting number still checks out as a 307. there is no stamping on the pistons saying that it is bored over. im not sure...give me some input...
 

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Discussion Starter #13
DeathRattle said:
What is the casting number of the block?
the casting number is 3970020. i have checked on 2 different websites and it says that it is a 307, but the bore does not match, and some of the people say that it is not a 327 crank like it is supposed to be.
 

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bigdome16 said:
the casting number is 3970020. i have checked on 2 different websites and it says that it is a 307, but the bore does not match, and some of the people say that it is not a 327 crank like it is supposed to be.
dont always believe the numbers, i was going to sell a 327 mtr to a fellow member, we even checked the ####'s. well the ##'s said it was a 327 BUT after he check the bore it was a 307. here's the POST on it ..joe
 

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Numbers, shumners..... :rolleyes: :rolleyes:

Go look at the information given in post # 9.

It is a 350. If it were a smaller engine, the metal between bores would be wide = 3/4 inch or 1 inch wide.

Since it is apart, measure the stroke from piston down, to piston up....... 3.48 on a 350. You already know the hole is 4.00. :rolleyes: :rolleyes:
 
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