Slingshot manifold

34roadsterpickup

Junior Member
I have a 1938 stock flathead.It was rebuilt back to stock.I am putting an original Eldelbrock Slingshot manifold on it.I am not sure of the best carbs to put on it? What size jets? Any help would be appriciated.
 
I'm doing basically the same thing on a rebuilt stock (except for 0.030" over bore) '35 221 engine. I'm planning to use Vern Tardel's Y adapter and two Stromberg 81's with stock jets and PV's. I'll be using non progressive tandem connected linkage.
 
I don't know if I'd use that Y adapter (OK I wouldn't). Aren't you stuffing two carbs down one hole? Think you might run a little rich??
 
you can run 81s (smallest of the typical Stromberg's) or 97 or whatever you wish, either carb can be rejeted for the tandem set up. I have two 97 the mains are 43 and the PVs are 69, these are on a 21 stud. If you run 81s or 48s (largest of the typical carbs) this will change. Suggest you contact Uncle Max when you decide, and he can guide you.
 
Motor City Flathead has done some 'dyno' work on this. They found inlet manifolds which have the inlets over the engine ports (further apart rather than closer together), combined with Holley '94's' gave better performance and economy over other set-ups.

Mind you we're not talking about huge margins of difference. MCF found the Holleys were a little trickier to set up but they performed a little better than Strombergs. But the good news is they achieved a 5% gain in fuel efficiency while having a peppier engine.

I can't remember how they set the Holleys up, but that information is readily available.
 
I just picked up a repro slingshot and was planning on 97s on a stock motor. Haven't decided on a linkage set up yet.

You have an original? Jealous...
 
I don't know if I'd use that Y adapter (OK I wouldn't). Aren't you stuffing two carbs down one hole? Think you might run a little rich??

I'm just experimenting with some existing parts that I already have. If it runs too rich, I can always re-jet and maybe change PV's in the 81's or just go back to the single 97. I also have a Thickstun 2x2 that I could use but would rather not take the original manifold off of an almost all original car. Just my way of doing things and having some fun with my old Ford. Thanks for posting your concern though.
 
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