Anyone With Chevy 350/383 Knowledge?

Hepar

Hepar

New member
I just recently picked up a restomodded 1948 Chevy convertible. Came with a 383 stroker crate engine. Currently it's setup with two breathers. I know that a lot of people who run this engine run it with one breather and a PCV valve. I will whole heartily admit that I know NOTHING about this engine. Should I change the setup?

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Ive seen a lot of small block chevys run with the breathers, and never heard of any reason it was a problem.
If it bothers you, it would be cheap to go to a pcv set-up, but as long as the breather doesnt get clogged and the car is running good, Its probably fine.
The pcv just returns vapors from the crank case into the intake to be re-burned, but as long as the vapors can escape, its not hurting the motor, I think it just lowers emissions
 
Limbwalker said:
Ive seen a lot of small block chevys run with the breathers, and never heard of any reason it was a problem.
If it bothers you, it would be cheap to go to a pcv set-up, but as long as the breather doesnt get clogged and the car is running good, Its probably fine.
The pcv just returns vapors from the crank case into the intake to be re-burned, but as long as the vapors can escape, its not hurting the motor, I think it just lowers emissions
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Thanks for the intel.

Limbwalker said:
Oh, and more pics please. Looks sweet
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It is sweet! I can't wait for the weather to get better!

<a href="http://www.flickr.com/photos/jkusuiphotography/10566614714/" title="DSC_3753 by JKUsui Photography, on Flickr"><img src="http://farm6.staticflickr.com/5537/10566614714_1740ce4421_b.jpg" width="1024" height="698" alt="DSC_3753"></a>

<a href="http://www.flickr.com/photos/jkusuiphotography/10566576206/" title="DSC_3750 by JKUsui Photography, on Flickr"><img src="http://farm6.staticflickr.com/5544/10566576206_b52c820918_b.jpg" width="1024" height="610" alt="DSC_3750"></a>
 
Limbwalker said:
Ive seen a lot of small block chevys run with the breathers, and never heard of any reason it was a problem.
If it bothers you, it would be cheap to go to a pcv set-up, but as long as the breather doesnt get clogged and the car is running good, Its probably fine.
The pcv just returns vapors from the crank case into the intake to be re-burned, but as long as the vapors can escape, its not hurting the motor, I think it just lowers emissions
Click to expand...

Yep, breathers just vent the crankcase vapor to the atmosphere. PCV systems were invented to eliminate that source of pollution.

Since the number of street legal cars like the OP's are miniscule in comparison to the number of modern emissions cars on the road, and the fact that classic cars aren't driven that much anyway, I'd just leave it alone and enjoy it.

Nice car, Hepar. :cool:
 
My opinion - FTW - ditch the carbs and go with EFI! There are lots of aftermarket EFI kits that will do wonders for your great looking ride!

:flamethrwoer2:
 
RiFF RaFF said:
My opinion - FTW - ditch the carbs and go with EFI! There are lots of aftermarket EFI kits that will do wonders for your great looking ride!

:flamethrwoer2:
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Thanks for the two cents, but I actually like the carbs. Nice and simple.
 
As others have said, forgo the PCV valve.

That is beautiful. Someone put in the wrench time on that thing and then some.

How many miles?
 
Beautiful Truck


Dammit.....I think I am in love. That thing is freaking cool to the max!!
:clap2::dance:

A "383" is always thought of as a Dodge/Plymouth engine (which it was in the late 1960s) -- but a Chevy 383 (if I remember correctly) is a small-block 350 with a crankshaft from a 400 small-block. They were not the most streetable engine, but would run like stink when you took it to the strip.

This is sort of like the "302" (usually associated with Ford) that Chevy put out for the 1969 Camaro Z/28. It was a 327 small-block with a 283 crankshaft. They did this to fit under a 5-liter size limit for homologation purposes - and few people truly had a clue about how much power they put out.

Ah, thanks for making me remember some of the 'good old days' of GM muscle!!

:israel::target:
 

As for the 'breathers' vs the PCV? Leave it as is.....and also KEEP the carburetor. Nothing like the sound of a 4bbl gasping for air!
 
Thanks guys. Appreciate all the info!

Oh and just to clarify. This beauty isn't all mine. Some friends and I went in on it together, but I'm the one with the garage space!
 
Nice ride!

You can run the PCV and it won't hurt anything. The minute amount of performance you might give up won't be noticed.

I run a PCV valve in my 68 Firebird. The car has a 400 with Ram Air heads and a Crower cam. The motor's pushing out just over 425HP and it has a PCV valve.
 
Actually the 383 Chevy is a great streetable, torque engine perfect for trucks, 4Xs, and heavy cars. U are correct in that they used a crank from a 400sb. They cut the main journals down to fit the 350 block. However, these cranks were never forged so the guys building big HP didn't use them. A less known version was the 373, which used a forged steel 350 crank in a 400 block. Bigger bore, shorter stroke high winder! The only drawback was the siamese cylinder bores in the middle of the block which could cause overheating in extreme conditions as there wasn't a water passage between them. Man do I miss my Chevys!
 
Super-G said:
Nice ride!

You can run the PCV and it won't hurt anything. The minute amount of performance you might give up won't be noticed.
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That's true.

But the amount of pollution it would clean up is also insignificant on a rarely driven, carbureted, gas tank venting to the atmosphere, non-catalytic convertor equipped classic car.

I wouldn't install a PCV system, just because it would clutter up the look of the engine.
 
Hepar said:
I don't believe you. I'm going to need to see pictures. And lots of them.
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HA HA I can take a hint. It's a 68 Firebird with a 400 punched .030 over. It has a set of mildly ported Ram Air III heads, a Crower 60243 cam, Edelbrock Performer RPM intake, and a modified Rochester Q-jet carb. It has a Muncie M-20 4 speed trans and it has a 12 bolt posi rear with 3:73 gears.

68Firebird042_zps1d3a358e.jpg~original


68Firebird039_zps4cd5b446.jpg~original


68Firebird009_zpsc339a34c.jpg~original


Here's a motor shot. If you look at the rubber line coming up from under the intake to the base of the carb, that's my PCV line!

68Firebird035_zps45ebd334.jpg~original
 
I ran a PCV and breather on my truck with a 357 (350 that's 40 over) and my dad runs both breathers in his chevelle with a 355 (350 punched out 30 over), I just ran the PCV on mine because the builder told me to. I honestly did not like it because I felt that my vacuum was always inconsistent and I was always messing with the idle mixture screws and fast ide control trying to dial it in with proper vacuum and the chevelle was always dead nuts consistent no vacuum leaks or inconsistencies and always ran a solid 11.5 in/Hg at idle even with a massive cam. My motor was the same but 40 over with same heads, similar cam, same vacuum advance dizzy, everything but always had tuning issues.

Also, Summit Racing has a tech help line that you can call and explain what you have and how you use it and they can definitely lead you in the right direction. Really intelligent technically skilled guys working the phones there.
 
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