330HP 350CI crate engine into a 1957

[Theodore K.]

I have been seriously been considering my 1957 Corvette as the old engine cannot be bored and is getting tired. One of my options is to buy a new 330HP 350CI Chevy crate engine and install it. There may be numerous challenges in installing it and getting it to work. Included is the problem of crankcase venting. Has anyone done this conversion and are they willing to share their experiences. I do have other options including rebuilding another 57 engine I have. However, I would like to explore the 350.Your comments are appreciated

[Joe L.]

Re: 330HP 350CI crate engine into a 1957

I have been seriously been considering my 1957 Corvette as the old engine cannot be bored and is getting tired. One of my options is to buy a new 330HP 350CI Chevy crate engine and install it. There may be numerous challenges in installing it and getting it to work. Included is the problem of crankcase venting. Has anyone done this conversion and are they willing to share their experiences. I do have other options including rebuilding another 57 engine I have. However, I would like to explore the 350.Your comments are appreciated

Theodore------


Crankcase venting is not a problem IF you use the crate engine with a PCV system as it is designed to use. If you want to maintain the original valve covers, that's another story.

As I have mentioned before, I think it would be possible to bore a hole in the rear of the block, into the lifter valley. By installing a fabricated oil separator in the lifter valley and connecting it to the hole with an appropriate fitting, either the road draft tube or a C1 or C2 style PCV system could be installed.

Another problem that occurs if a 330 hp 350 is used is that this engine uses Vortec heads. This means you cannot use your stock intake manifold (with oil fill tube), so that presents another problem for a crankcase ventilation system. I don't know how to surmount that problem unless there is an aftermarket intake manifold I'm not aware of that's designed for Vortec heads and has provisions for a filler tube.

If you were to go with a ZZ4 engine, you eliminate the manifold problem. With that engine conventional intake manifolds can be used, so you could install your original manifold on this engine. Of course, the ZZ4 is quite a bit more expensive than the 330 hp 350.

[Steven B.]

Re: 330HP 350CI crate engine into a 1957

I don't have an answer for the intake manifold. There are adapters available that bolt to the heads and allow use of the old style valve cover bolt pattern. For oil fill you would have to use LT-1/L-82 covers if you don't want to modify C1 covers.

Can you bore your original block +.030 or +.040?

Steve

[Michael G.]

Re: 330HP 350CI crate engine into a 1957

Hey Joe,

Is the ZZ4 engine compatible with other old small block 265-327 components, such as exhaust manifolds, water pumps, etc?

Thanks,

[Tom P.]

Re: 330HP 350CI crate engine into a 1957

Joe raises valid points above. You will have to sort out which direction you wish to go with a later engine. BUUUUUT, the traditional first design small block V8 (more or less) is virtually a 100% bolt-in swap.
I'm running a SB400 in the 56 with a home made PCV system and solid (NO HOLES) 9 fin valve covers. Oh ya, and the staggered bolt pattern 9 fin covers are on later straight across bolt pattern 2.02 heads (I had extra bosses welded, drilled and tapped in the heads).
My point is that a 68-later SB's (no hole in the rear of the block for road draft tube or PCV provision) CAN BE modified and/or setup to provide adequate crankcase ventilation. I've seen some engines that have a hole with a grommet and PCV valve installed behind the intake runners for #7-8 cylinders that is virtually hidden. Works great.
Here are a few pictures of the PCV method I devised for the SB400 in my 56. The PCV valve itself is a generic replacement for a 63 FI car, which has the same valve installed on the opposite side of the FI plenum.

[Theodore K.]

Re: 330HP 350CI crate engine into a 1957

I don't have an answer for the intake manifold. There are adapters available that bolt to the heads and allow use of the old style valve cover bolt pattern. For oil fill you would have to use LT-1/L-82 covers if you don't want to modify C1 covers.

Can you bore your original block +.030 or +.040?

Steve

Steve, the present (non original, but correct casting date) block has been bored +0.125" already and can go no further. It would have to be sleeved. It has quite a bit of taper to it and that adds to oil consumption. The engine has domed pistons and 997 heads and pings like crazy, and I am getting tired of using straight 100 Octane LL Avgas. Make road travel a nightmare anymore. ...Ted

[Joe L.]

Re: 330HP 350CI crate engine into a 1957

Hey Joe,

Is the ZZ4 engine compatible with other old small block 265-327 components, such as exhaust manifolds, water pumps, etc?

Thanks,

Michael------


The ZZ4 engine is compatible with virtually all small block peripherals. The exhaust ports are raised 0.1", but I believe that stock small block cast iron manifolds can be used, possibly with some slight adaptation. All Gen I small block waterpumps are bolt-on.

Other components like bellhousing, starter, and generator brackets are bolt-on. The flywheel must be an 86+ style for use with a 1 piece seal crankshaft, though, but otherwise C2-C3 clutches can be used. Any 57-74 distributor can be installed as long as the distributor drive gear is changed to the melonized gear for use with the steel roller camshaft. Mechanical fuel pump provisions are present and any mechanical fuel pump can be used.

The ZZ4 will accept either C1 style motor mounts or C2-C3 style mounts. All small block pulley systems are bolt-on.

For a little more money one can upgrade to the "Fast Burn 385" which is, basically, the ZZ4 with fast burn cylinder heads. However, if I recall correctly, the "Fast Burn 385 is supplied only as a "fully dressed" engine which includes a lot of components that one might really not want to use for a conversion.

Neither the aluminum heads supplied with the ZZ4 or the fast burn aluminum heads supplied with the "Fast Burn 385" have provisions for exhaust heat cross-over. So, neither divorced style chokes nor heat riser valves can be used.

Original 55-79 oil pans cannot be used due to the 1 piece rear main seal configuration and right side dipstick.

[Joe C.]

Re: 330HP 350CI crate engine into a 1957

Who put the snake in Tom P's lifter valley?

[Patrick T.]

Re: 330HP 350CI crate engine into a 1957

In the early '90's I had a '57, with no engine or trans. I put in a new crate ZZZ 350/345 hp and a new Holley 750 double pumper carb. I used some stock exhaust manifolds from the 50's.

I bought a used 50's era generator with the power steering gear out of the back and used that to mount a tach drive. I also needed to change the water pump to a short neck pump. That was it, the motor dropped right in with no problems and it ran like a scalded cat. PT

[Tom P.]

Re: 330HP 350CI crate engine into a 1957

I did. Believe it or not, it works. The (3) holes to allow crankcase vapors to escape are in the cap at the very forward end of the plumbing. After various configurations, this is the one which works. By having the holes at the very front, almost up against the front wall of the lifter valley, this prevents oil splash from getting into the plumbing. Thus, for the most part, only vapors enter the plumbing. Doesn't matter what it looks like, it's covered up with the FI manifold and it (so far) is very functional! Laugh at it all you want, it works!!!!!!!!!!!!

[Joe C.]

Re: 330HP 350CI crate engine into a 1957

I did. Believe it or not, it works. The (3) holes to allow crankcase vapors to escape are in the cap at the very forward end of the plumbing. After various configurations, this is the one which works. By having the holes at the very front, almost up against the front wall of the lifter valley, this prevents oil splash from getting into the plumbing. Thus, for the most part, only vapors enter the plumbing. Doesn't matter what it looks like, it's covered up with the FI manifold and it (so far) is very functional! Laugh at it all you want, it works!!!!!!!!!!!!

I believe it! Actually admire your ingenuity.
Just one suggestion, to avoid any sudden heart failure issues. You should post a decal under your hood as a warning to any (possible) future owners of your car. The decal should read:

WARNING: Removal of intake manifold will release wild snakes. Use caution!

Here's how I made a lifter valley splash pan work with the old fashioned vapor separator.

[James G.]

Engine Balance Internal Vs. External

PLEASE BEWARE !!!
The ZZ4 and newer engines are BALANCED WITHIN the assembly. So if you bolt on 57 flywheel, and clutch assembly you will get HUGE VIBRATION.

Check with your CHEVROLET PARTS DEPT for compability.

[Joe L.]

Re: Engine Balance Internal Vs. External

PLEASE BEWARE !!!
The ZZ4 and newer engines are BALANCED WITHIN the assembly. So if you bolt on 57 flywheel, and clutch assembly you will get HUGE VIBRATION.

Check with your CHEVROLET PARTS DEPT for compability.

Jim------

Yes, that would happen IF someone figured out a way to install a 1957-85 flywheel on a ZZ-series engine. However, I don't know of any way to do this. The flywheels used for 1957-85 Corvette engines are designed for installation on 2 piece seal crankshafts. All ZZ-series engines utilize a 1 piece seal crankshaft and, consequently, a flywheel with a mounting pattern specific to those crankshafts. So, if one uses a ZZ-series engine (or, any engine with a 1 piece seal crankshaft), then one pretty much can only install a flywheel designed for those engines.

However, a 57-85 clutch can be used with the 1 piece seal crank style flywheels as long as the clutch is the correct size and bolt pattern for the particular flywheel used.

[Jack H.]

Re: 330HP 350CI crate engine into a 1957

A consideration that can elude folks doing conversions is the thermal profile of a factory non-stock motor. Once the 'plumbing' and other fit considerations are solved and the new motor is neatly tucked into the engine compartment, you MAY need to do radical surgery on the radiator & related cooling components...

Raising max HP under the hood typically goes hand in hand with raising max BTU heat dissipation in the engine compartment as well. So, consider the spectre of melting underhood wiring and overloading the factory original cooling system...

[John H.]

Re: 330HP 350CI crate engine into a 1957

A consideration that can elude folks doing conversions is the thermal profile of a factory non-stock motor. Once the 'plumbing' and other fit considerations are solved and the new motor is neatly tucked into the engine compartment, you MAY need to do radical surgery on the radiator & related cooling components...

Jack -

That's why Tom DeWitt invented the A 5 5 M direct-fit aluminum radiator, which is a direct bolt-in, for C1's originally equipped with copper/brass radiators.