1968CutlassSupreme

Hello All!

I have a couple questions:

I am concerned about the placement of the gas tank vent tubes. They are on the passenger side, being merely clipped in the "opening facing up" position (where the tube openings are facing the underside of the floor board) right next to the exhaust pipe. Is there a way to make this safer (it seems venting gas fumes next to a hot exaust pipe might me a tad dangerous)?

Does anyone know where I can get a set of 350 H-Beam connecting rods? I found some for the 455 but I cannot seem to find them for the 350.

Thanks everyone!

hookem horns

That's how the factory did it. Do you have the small "surge" connector at the top of the vents? Often missing but repops are available with the usual high premium for a small chunk of plastic. Allows any fuel that burps up one vent to drain down the other.

1968CutlassSupreme

I don't have the "surge" connector. Where can I find one? What does it look like? Would that be better than trying to find some sort of vent (like a miniature version of the crank case vent in the valve cover)?

66luvr

IMO, the purpose of the tank vent is to move air, in and out of the tank. That air only needs to move very slowly and in very small amounts. I didn't really dream all this up, I bought repro vent hoses for the 67 Cutlass I had. One of the hoses had a piece of open cell foam in it. So I developed this theory with that in mind. So I wasn't happy with only one tube being "baffled" so I took a piece off a new lawn mower filter I had and inserted it into the other hose making both the same. Then I blew through both, they moved air but it moved slowly. Here comes my "figuring", the air needs to move but slowly, if gas sloshing around can't displace the air quickly enough to get into the vent tube then fuel can't escape. So you can stuff some foam into the hoses or get the mentioned cap, both should work.
http://www.ebay.com/itm/69-70-71-Che...4d4124&vxp=mtr
http://www.ebay.com/itm/69-70-71-Che...c8b0d7&vxp=mtr

If you don't like where the rubber lines are located put longer ones on and locate where you like. Make sure they run in the up direction and add the filter/baffle. Allowing them to run down could allow fuel to get into them.

cutlassefi

Mondello has the H beams but the jury is still out on their quality.
What are the build specs/goals?

Smitty275

The 6" H beam 350 rod is a myth. I actually ordered a set from the an over seas manufacturer who lists them on their website and have not received them after almost 6 months. Basically they did a couple sets and do not know if they will get back to them. The ones that are advertised by Lyndellos and their other web based name have been reported to be junk quality at best and returned by several people who swear they all got the same set of rods.

1968CutlassSupreme

Mark,

I am trying to help Brad find some connecting rods for a mild rebuild (about 350/375 HP). If we cannot find rods, we will rebuild the originals and use ARP bolts, I suppose. I posted a new thread showing my "overhaul." Basically I am doing a "better than stock" rebuild but nothing crazy.

We are aiming for a 10:1 (or so) compression so I can stick with 92 pump gas. The heads are #5 heads, ported and set up for the larger 2.00" intake and the 1.67" exhaust valves, and the chambers are 53cc each. The pistons we are considering forged aluminum and are slightly dished (less than flat but more than stock).

The block is going to be decked, squared, bored (.030 over) and honed. The original crank will be polished and balanced (externally with the balancer and the flexplate).

We will be replacing all the bearings and seals. I am looking into a melling high volume oil pump as well.

The intake / exhaust will be a 600cfm Edelbrock Carb/ gasket matched 7111 Perfomer intake, with gasket matched American Racing headers (1 5/8).

Ignition will be HEI.

Nothing fancy but exciting none the less.

Here is the thread I referenced: https://classicoldsmobile.com/forums...n-edition.html

cutlassefi

So you're using a 600cfm carb with ported heads? Why?


Imo you've missed the combination a bit.
With ported heads I'd do a 750, nothing less.
1 3/4 headers
Standard pump shimmed .250
You'll need a dish of 20cc or so in order to hit 10.0:1 with 53cc heads. Keep the smaller exhaust valve, 1.62.
Why not use a SBC rod bushed for a .980 pin. Stronger, much lighter, and readily available.


Jmo.

1968CutlassSupreme

I am using the 600 because of a recommendation. That may change when the engine is done and running, but it is what I have for now.

As for the SBC rod question, I do not have the extra $750 for crank work in order to have the crank ground for the chevy rod, otherwise I would do that.

Smitty275

Who's gonna rock you $750 to take .025 off the rod journals to go to an SBC rod? Thats ludicrous. You can ship it here, have it ground, and shipped back for less than half that. Only catch is you then need to use a piston with .927 pin.
I can throw a 3.500 stroke and 2.000 journals shipped both ways for less than $750. Or forget shipping one here and I'd have one done out of the stock rack and ship it.

cutlassefi

Ditto. My guy charges $250.00 to grind to small journal size and 3.500 stroke.
Sounds like you're getting stroked.

1968CutlassSupreme

Mark,

What is the benefit of the 3.500 stroke? Would the rods still be readily available? What is a reasonable price for the chevy rods and a set of .030 pistons (along with the wrist pins and rings)?

Anyone else can chime in as well...

Thanks everyone!

The Stickman

Hint Hint


https://classicoldsmobile.com/forums...ker-crank.html

cutlassefi

Pm'd you.

cdrod

I'm getting closer to building my engine and curious to know this as well.

cutlassefi

More stroke, more cubic inches, more power and torque.
Any good SBC I beam rod will do, just make sure it's not made with 5140 material. Not worth the money.
Then just look for a SBC 400 piston with either a 1.550 or 1.425 compression distance (depending on the rod you're using) and go from there.
All those pieces are lighter, stronger and more readily available than the stock stuff.