[allansmith859]

Is a 305 Crank the same as a 350?????

[68NovaSS]

Depends on the year, some early 350 cranks were small journal, and came steel, cast and forged. IIRC, there were no forged 305 cranks, but all were large journal. Here's some data.

[F-BIRD'88]

A used GM 305 crank is balanced for 305 pistons. A used GM 350 crank is balanced for the 350 pistons.

rebalanceing a 305 crank for a 350 can be expensive (mallory metal)
Cheaper to just trade for a 350 crank and work with that.
Its not like they are rare. Your local engine rebuilder shop will have good 350 crank cores and will take your 305 core for trade/ partial trade.

[lg1969]

There are cranks that is used on a 305 and 350. There are no small journal 350 cranks.

[allansmith859]

Ok this is what I found out. This crank (3932442) is the one I pulled out of my 85 Z-28 motor (305), but its also the same crank that is in my 350 engine.

So since they are both the same could I use the one out of the 305

Here is the info for the two cranks:

1969 - 85 (The engine was in a 1973 vehicle)

The crank was used in 305 and 350's and in 1979 -1982 267 cid

Cast Nodular Iron

Large journals

2 peice rear main seal

[F-BIRD'88]

The balance is different for each different motor.
the cost to correct the balance is moe than the cost of a usable 350 core+ the regrind. Someone will buy your 305 block and crank to build a 305.

[lg1969]

It's no different what was used on a 283 crank is used on a 302, or a 307 crank is the same crank used a 327.

[allansmith859]

So I guess Im better off selling the 305 block and the 305 crank and keeping the 350 with its crank. I planned on building the 350 but just wanted to know if the two cranks would interchange.

Thanks guys

[F-BIRD'88]

You are making many different threads about the same engine build project.
you have the option of building a mean 305 SBC also.

You just have to know how.

[68NovaSS]

Originally Posted by lg1969

There are cranks that is used on a 305 and 350. There are no small journal 350 cranks.

Thanks for the correction, I must have had 327 cranks on the brain.

[allansmith859]

Well I actually planned on building the 305 in the first place but after doing research people say its a waste of time to mess with the 305, is that true.

[F-BIRD'88]

Originally Posted by allansmith859

Well I actually planned on building the 305 in the first place but after doing research people say its a waste of time to mess with the 305, is that true.

Depends on how you look at it.

A 400hp spanking street strip 305 w 10.5:1 compression and ported big valve 305HO heads is not hard to build.

A spanking B&M blown 450hp low compression ratio 305 is not hard to build.

These 305 engines want to rev high and when souped up want a steep gear and converter.
Thats the biggest difference between a built up 305 and 350 of comparable power output.
same cat just a different way of skinning it.

A built 350 gets it done too.

[allansmith859]

Let me ask you this. The heads that were on the engine were HO. would they be worth using and have sent in and checked for cracks and cleaned up?

[junior stocker]

Although factory GM 305 and 350 cast cranks have the same casting number, they are "balanced" differently. A 305 application crank has a target bob weight of 1600 grams, while a 350 application crank has a target bob weight of 1850 grams. These are factory numbers, aftermarket balancing is much more accurate.

[bondo]

Originally Posted by allansmith859

Let me ask you this. The heads that were on the engine were HO. would they be worth using and have sent in and checked for cracks and cleaned up?

Nope.... 305 heads on a 350 is not an ideal setup...