blaker1

Hey everyone! I have a 67 cutlass with the 330 with the 2 speed. Its the original engine and tranny and works ok. It is in a definate need of a rebuild works great, just tired. Seeing as how im tearing the car down anyways, I stummbled on a 350 out of a 68. Fairly low milage and needs a minor refresh aswell. Does anybody have any opinions? I think it would be a good idea to replace my 330 with the 350, as they are more common. I was also thinking will the 330 heads on the 350 be a good route for compression? or should i just stay away? Want a good amount of snap but i dont need the car to be stupid fast or complete money pit. Thanks for any help!

oldstata

From my understanding you can put the 330 heads on with no problems. Not a 100% on this I think you have to make sure that it has the 39degree cam will see if some one can chime in on the heads alittle more I would use the crank out of the 330 as well since it is a forged crank .

blaker1

excellent thank you for the insight ive heard alot that the 330's are quite a bit tougher aswell

captjim

Some 330 blocks (early) had the cam issue, but that is the block and has nothing to do with the heads. If the 350 runs good, leave it alone, the bump in compression is not really that much and might be offset by the replacement head gaskets, depending on what the 350 is using. But otherwise, those 330 heads are a direct bolt on.

Chesrown 67 OAI

if your 350 heads are #5's -- you cant get any better than these for your street motor!! Only way you would want to consider using the 330 heads (#2 or #3) would be if you had just had them all rebuilt and didnt want to go to expense all over again doing a rebuild on the #5 heads. Get those #5s rebuilt and you will be happy!!

oldsmobiledave

1967 #4 cylinder heads are a direct bolt on to any 1968-1976 350. With enlarged head bolt holes they will also work on the later 350 & 403 blocks. They are the only factory cylinder head with 64cc chambers. The #5 #6 #7 heads are all 68-69 cc chambers.

There is no truth to #5 heads being "the best". They are no better than #6 or #7 heads & are actually inferior to the #4 heads. #6 W-31 heads are certainly better than stock #5 heads.

Re use your #4 heads...they are the BEST!

Chesrown 67 OAI

X2 Agree -- the 67 #4 head, according to NHRA Spec guide has a minimum cc of 58.19 and the #5 for 68 W-31 is 60.6 so when prepped to these specs the #4 67 head would produce a bit more compression.
As for #6 W-31s being any better than #5 W31s is "questionable" -- The flow bench is the only answer to which head is "best"!!

In the case above I seriously doubt if there were any noticible difference in the street motor using either the #4 330 or #5 350 heads.
So he cant go too far wrong with either one if he gets them a good rebuild!! (MOO)!!

captjim

Keep in mind that if the 350 is OE and he puts the 330 heads on it using Fel-Pro gakets, the extra thickness will negate the smaller chamber.

blaker1

all very good information its a couple months down the road so i do have time to think im leaning towards the 330 heads on the 350 if they are the #4's

oldstata

Another idea could be bore out the 330 and use the 350 pistons read some where this make a ton of hp for a small block I will see if I can find the link again

captjim

Why would it make a ton of HP when all you end up with is 350 CI?

Also, stock 330 bore is 3.938 vs a 350 4.057 bore. That is a .119 over bore, that woyuld be a lot more expensive than a 350 block.

captjim

Why?

oldstata

Your right when I went back and looked they basically built the small block cost wise in the end still would be better to just go bb

Seff

Are you sure you're not misremembering a 350 diesel job with 425 pistons or something like that?

captjim

That is a blanket statement that is not always true. While the cost is similar and cubes rule, there are applications where the small block is preffered. So "better" really depends on what you want. Want to keep it original? Low 14 second street car that gets decent mileage? SBO is fine. High 12s on pump gas? BBO probably a better choice.

joe_padavano

You will never see a difference replacing the 350 heads with the 330 heads. They are equivalent castings. Keep in mind that the NHRA numbers are blueprint minimums, NOT as-cast. The as-cast chambers are typically 2-6 cc over the blueprint and more importantly, there is that much variability in them from one hole to the next and one casting to the next. This is production tolerance and this is why you should blueprint a performance motor. NHRA stock specs are not "stock" but are the most advantageous dimensions you are allowed to run in that class. They are the factory minimum tolerance numbers. Normal production parts will be above this.

Unless you plan to machine the 330 heads to the blueprint numbers, there's no guarantee that you'll have that chamber volume, and if you ARE planning to machine them, there's no difference in machining 330 or 350 heads to the same chamber volume. Finally, you you really think you'll see a performance difference in a 2-3cc change in chamber volume?

dpt618

Octania

Why would a 0.060" bore cut cost a lot of money? several passes? Just get 030 pistons and use the 350 block then.

Use your best parts, but be sure to balance the recip assembly.

I would dismantle all then pick the best pieces, favoring
330 crank, balancer, flexplate
403 rods
#4 heads
Whichever block works bore-wise. ask the machinist about $ to bore 330 to std 350 size, and see if you can still get std size flat top W31 pistons.

Ah a mere $72 each, the price of an entire SBC rebuild kit
http://www.jegs.com/i/Sealed-Power/8...rentProductId=


Either the 4 or 5 heads leftover should be easy to sell.

captjim

Do you realize that this thread is over two years old?