F.A.S.T. questions

[VintageMusclecar]

Asking purely hypothetical questions, of course...

Say someone were to contemplate building a `67 L78. The OEM heads are casting # 3904391, the carb is a #3910 and the intake is a #3885069. All rather expensive items in comparison to their more common 840, 4346 (et.al.) and 163 bretheren.

Would 840 heads, 4346 carbs (or any other similar design 780 GM carb) and a 163 intake be legal substitutes?

Next question: Did the F40 HD suspension option on `67's include a rear sway bar? If so, are aftermarket replacements legal? Do they have to be OEM diamater?

Last question (for now, anyhow);

F70/14's were an option on `67's. Do I understand correctly that a G70/14 is an acceptable upgrade, as long as the original 14X6 rim is maintained?

Thanks!

Eric

[Chevy454]

I *think* you'd be ok on the carb, but I think you're gonna need the right # on the heads/intake. And the sway bar...I'm not up on the early a-bodys, but on the later ones it took the F41 option to get the rear sway bar...but if you could get a rear bar on a '67, you can use it...and yes, you can upgrade to a G series tire.

Big dog or John Brown...did I miss anything?

And here's a link to the FAST page, with rules:

[John Brown]

Eric, I'm not the one you really need to the answer those questions. Personally I'd be a little more of a stickler on the parts than Rob since the carbs may be available repopped from Holley (or service dated and much cheaper), and the manifolds are available if you look daily on e-bay.

edit: rules now say stamp # on carb doesn't need to be correct if the carb appears externally correct.

The carb is a bunch small so you might want to find a shop that can massage the insides to make it flow a bit ( like 900 cfm) better too. Heads are another story. If they are flat not available and another casting # offers no performance advantage an exception <u>might</u> be made.

Look here for the F.A.S.T. rules.

F.A.S.T. rules

Sign up over there if you want to ask the guys that have final say if you can run the parts you are asking about.

F.A.S.T Questions

The G70x14's are ok, and if a rear sway bar was available in 66 I don't think anyone is going to measure it. Front sway bar is optional.

Hope you can see your way to building a 66 SS car. Those coil spring cars can really hook and a 66 is the lightest one available with a big block except for a 65 Z-16.

[VintageMusclecar]

Thanks for the quick response(s).

AFAIK, the 840 heads are essentially the same as the 391's...both square port closed chamber heads with 2.19/1.72 valves. I *think* the only significant differences have to do with which heads are drilled for temp senders, but I'm not 100% sure on that.

Just considering the cost of the 391's since they're so rare. Then to tweak them for performance use essentially destroys the re-sale value. Same thing goes for the 163 intake vs. the 069.

The carb size is no big deal. 780 cfm is plenty once the fuel curve is right.

Just kicking around some ideas right now, wondering what the options were.

Much obliged gentlemen.

Eric

[Chevy454]

Might even give Pure Stock a thought...you've got potentially got a tasty little combo there...

[John Brown]

How about a 325/350 horse version (hydraulic roller?) of the same car? That should really cut the costs down.

It was available with a turbo 400. Might see a big difference in the 60' times over a 4-speed. The ovals are supposed to flow pretty well. Gessler can even port that cast iron intake to make it lighter. Can replace the trans with any GM automatic in F.A.S.T.

[VintageMusclecar]

Rob;

Pure stock has crossed my mind...still kicking around ideas.

John;

My car is a `67 Chevelle SS396...if I put a small block in it my friends would dis-own me lol.

If the tire/suspension rules were a little more liberal, I'd consider building an oval port motor, but with the skinny tires, I don't want something with an abundance of steam down low. Easier to get the car rolling on skinnies by moving the power upstairs and running steep gearing.

Essentially building a street race style car (albeit a nice one instead of the usual clapped-out sleeper), same ideas &amp; technology applies. But I won't go into how I know those things.

[VintageMusclecar]

John;

dis-regard my mention of a small block, I mis-read your post and somehow saw "327" instead of "325."

(couldn't edit the previous post)

I'm a dolt.

[VintageMusclecar]

Just saw the rule about no automatics on 4-speed only applications. Nixes the L78 idea for now.

Beginning to think this is a dead combination unless I swap over to a 4-speed so I can run the L78.

The 325HP combo would be strangled by the dinky single-inlet snorkle air cleaner, and the 350HP version only gets a 585 cfm Holley.

Pure Stock...maybe. F.A.S.T. doesn't look like it's gonna happen.

Rats. (no pun intended)

[YENKO DEUCE REGISTRY]

I just dug out a service dated 3910, 822 I think, just the main body - not even choke plate. So, if you want to build the combo, let me know and we can it to ya!