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Old 12-30-06, 04:15AM   #1
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Join Date: Dec 2006
Location: Anytown, CA
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Default Formual 400 help. 1/4 mile trouble?

Here is car info:
70 Formula 400
YS Code 400
Holley 650 Carburator
Stock cam
Stock heads
Stock intake
Stock rods
Stock crank etc. All car is stock
Hooker Super Comp Headers
2.5 inch exhaust, X pipe and Flowmasters
12 bolt LSD rear, 3.55 gearing

Car is stock weight of 3310 lbs, AC removed

Engine has not been rebuilt, 90K on it.
330hp and 430 tq car

TH350 transmission
Tires are 245/60/14

Nothing except for the exhaust has been done, needs body work.

1) What did the auto non-ram air cars run in the 1/4 mile
2) What is needed to make mine run a mid 13 without heavy engine work
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Old 12-30-06, 04:46AM   #2
Got Posi?
Join Date: Jun 2005
Location: AnyTown USA
Posts: 4

From what I have seen in person, with a numbers matching Formula 400 at the strip, Identical to yours but with exhaust manifolds, Q-Jet, and TH400. It ran a 14.02. I would expect your car to be in the mid 14 range. It won't run like it did when it came off the showroom floor 30+ years ago.
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Old 12-30-06, 10:26PM   #3
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Join Date: Nov 2005
Location: Fountain Colorado
Posts: 493

I'd be careful racing it real hard. With 90K, you'll have alot of loose tolerances as well as ridges at the top of your cyl walls. Too much stress/stretch could break a ring.
78 T/A 463, Ultradyne custom cam, very ported Greg Merrick Heads, TH400, 3.31 12 bolt, 3425lbs

81 T/A 350 sbc vortec heads 4 speed 3.42 posi
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Old 01-03-07, 04:37AM   #4
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Join Date: Jul 2002
Location: La Jolla , California
Posts: 3,564
Default What ET is the car doing now?

Hope you are not trying to do this with todays pump grade gasoline with an original engine.
Those YS code engines were sittin' @ around 10.0 : 1 when new.
Todays low octane pump gas will pound the bearings out of it even with a conservative( extremely retarded) tune up. 96 to 100 octane was required for those engines.
If you are driving this car everyday the tuneup may already be way off to compensate for the low octane gasoline.
A compression test & leak down test will tell you if you still "have an engine".
@ 90,000 miles on the clock (car is 37 years old . I put 300K on my 1970 350 'Bird before I parked it in 2003. It had 95K on it when I purchased it in 1976 .Are you sure yours hasn't turned in 100K already?)
A 1970 Pontiac 350 2V engine had a CR of about 8.8:1 and they would rattle on 91 octane premium without some serious re/de-tuning
Before doing any racing I would replace the original timing chain and gears.
These are on borrowed time after about 75K miles.
If they let go or jump position the engine will just refuse to run.
The worst thing is when the plastic coated teeth on the cam gear let go they scatter all over in side the crank case which requires pulling the oil pan and cleaning out all the debris.If any of that trash gets by the oil pump pickup screen it can cause the gears in the oil pump to jam which can cause the oil pump drive shaft to shear.Engine keeps running with no oil pressure, for a while.You would be lucky if the roll pin on the distributor gear sheared first, then the engine would just quit.
Stock valve springs can be getting pretty tired at 150K ,I was breaking them at 225K.
Replace the distributor with a new MSD, Accel or Mallory breakerless unit.
Upgrade the coil too.
Is the ram air on the hood functional? If not make it so.
Low retriction air filter element(K&N).
You have improved the exhaust but have done nothing to the intake side.
Increasing air flow on the exhaust side may require richer jetting on the carb.You may find it's laying down on the top end ,too lean.
Put some good unleaded racing gas in it and play with the tune up.
(I suggest frehening up the engine before trying any of this though.)
Go out and do some base line runs.Keep your revs below 5700 rpm.
You will find there is a lot of ET to be gained by improving the 60' times .
This will involve gearing, rear tire diameters & widths , suspension reaction tuning / weight transfer.
8 to 10" wide sticky rear tires.
If you cannot change the rear gear to a 3.73 04 3.90 ratio go with the shortest sidewall tire on a 15" wheel you can find. 24" dia. to 26" max dia. would help out the 3.55 . 22" tall M/T ET drags are available but the weight of the car may preclude the use of them. You would want to consult with M/T first.
I think the 1970 cars had 14" wheels and those are hard to find slicks for.

Play it safe.
Step Away From The KOOL AID !
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