Stromberg 97 with ported vacuum

DSC_0726We have added an important new capability to our 97 model carburetor – a ‘ported vacuum’ source for your vacuum advance distributor. Available as an option (add -VP on to the usual carb part numbers) it is available on the full range of Stromberg 97 carburetors – in stock on the regular OE finish and to special order on Chrome, Black and Barn Find models. Ported vacuum capability is also available in a new replacement base casting (throttle body), complete with all new throttle shaft and plates, idle needle screws, kicker linkage and choke lever. Available only from Stromberg Carburetor, it’s the perfect swap-in for any 97.

Genuine Stromberg 97 with vacuum port – Part Number 9510A-VP
New 97 base with vacuum port (comes with gaskets) – Part number 9514-VP

Developed in-house here at Stromberg Carburetor, the new vac-port equipped 97s provide vacuum through a small brass fitting located just behind the kicker linkage on the same side of the carburetor base (throttle body) as the typical small-block Chevy distributor vacuum canister. The fitting can be replaced with a small set screw (supplied) if engine needs change.

Like our cable choke and ‘push-throttle’ options, the new vacuum port makes it easier to use 97s in so many applications. To test the effects on our 350ci Chevy dyno motor, we disconnected the vacuum and locked the throttle at 1800rpm. Once reconnected, the vacuum-induced additional timing raised rpm to 2000 and increased torque by 4 ft-lb – all without adding more gas, of course. The exhaust sound changed considerably, too, so it obviously appreciated the extra timing.

Tech note: Unlike manifold vacuum, ‘ported vacuum’ is taken from just above the throttle plate to provide additional, vacuum-activated timing advance only at light load/part throttle conditions and not at idle or full throttle. Claimed benefits of vacuum advance include improved fuel economy and throttle response. Most aftermarket vacuum advance distributors are designed to work with ported vacuum, though the technical specification should always be checked. And of course, multiple 97 applications need only one vac-port equipped carburetor.

The new Genuine Stromberg 97 with vacuum port and the new vac port-equipped 97 base are available through the worldwide Stromberg dealer network. Further details, including pricing, and help with installation is available from us here at Stromberg by email or via the Stromberg Tech Center at www.stromberg-97.com.

5/16in fuel lines for 97s

We recently launched some new fuel fitting parts so you can make 5/16in fuel lines for Stromberg 97s. While the stock early Ford 1/4in OD hard lines are great-looking for a typical flathead motor, many people like the thicker lines for Chevys and other applications. This includes us, of course, as our recently launched 9146-BIG 3-into-1 fuel line uses 5/16in OD stainless hard line. And more than that, all our forthcoming new Stromberg BIG 97s are 5/16in hard line compatible. You can see in these pictures how the BIG S-jet seats the 5/16in line and what happens when you try it in the regular S-jet – it leaves no seat for the ferrule. Click to enlarge.

Today we got a tech enquiry from Shane Dale in Australia that covers this very question, so we thought we’d share it here:

Hello, I have three new 97’s that I purchased in 2011 and am finally getting around to fitting up. I will be bending my own 5/16 OD hard line and was wondering what size fitting will screw into the carb? I purchased three 9180K’s and started hand screwing them but stopped quickly as it went tight.

Hi Shane, A couple of issues here. Firstly, 9180K is our 1/4NPT hard line adapter so the tapered NPT thread won’t fit into the S-jet, which is 1/2in UNF – that’s why it went tight. And as you worked out, regular Stromberg 97 inlet valves (needle & seats) were designed with a 1/4in pocket to take the line and the angled seat is positioned so the brass ferrule can compress properly to seal on the 1/4 pipe. If you put 5/16in line in, it doesn’t sit in the hole properly and covers most of the angled ferrule sealing surface. The good news is, we recently developed a new S-jet inlet valve for our 97s specifically for 5/16th line, and we also just launched a pack of compatible ‘Ford Nut’ style compression fittings for them. You need 3 x 9564K-BIG (the S-jet inlet valve) and just one pack (3 nuts and 3 ferrules in a pack) of 9081K-BIG (the Ford Nut for 5/16th line).

All the best, Stromberg Tech.