CG and CP-- distance from one to the other

[red54studebk]

car is 1972 Fiat 850 Spider with m cycle engine in rear - about same location as original car engine- wheelbase 79.8 inches- car length is 150.6 inches --- CP is located approx at base of windshield -- about how far  forward from CP should  we have the CG?  we are using lead bars and other lead weights as ballast .. we are looking for stability going down the salt and naturally trying to avoid a spin....i do know the saying... there are 2 kinds of people at Bonneville--those who have spun, and those who have not, but they will, later....thank you for info and help.

[Stainless1]

Where is your CG now?  What does your car weigh now? front weight?  rear weight? balanced left and right?    Bump Steer in front or rear suspension?  Amount of suspension movement?  Have you raced it on the salt?  How did it drive?
All that info and more helps determine what you need to do 

[Dynoroom]

If you are going to run in Modified Sports you may want to look over section 5.D.4 again in the SCTA rule book...

Engine placement is optional so long as no change is made
to the driver?s location as originally designed. The driver
shall be seated behind the engine, except in the case of
production and limited production bodies which are designed
for mid/rear-engine locations.

[manta22]

A Fiat 850 has a pretty short wheelbase. I think that will be your primary problem.

[Stan Back]

Stainless -- the motor is in the back stock.

[Dynoroom]

Stainless -- the motor is in the back stock.

Cool, problem solved...

[kiwi belly tank]

If it spins he'd be behind the engine,.... then in front of the engine,....
  Sid.

[panic]

Weight between the axles is distributed between them (duh), and increases traction (if only slightly).
Weight ahead of the front axle is much more effective at moving the CG, but is cantilevered, and removes weight from the rear wheels while adding to the front wheels.

[Stainless1]

Thus my questions...
Where are you located... do you have access to a set of scales? 

[tortoise]

-- CP is located approx at base of windshield -- about how far  forward from CP should  we have the CG?

You should certainly max out the spoiler spill plates per section 4.CC.8, figure 9 to move the CP back as far as possible. Are you committed to running a windshield? Are you committed to running stock wheelbase?