If you are installing new control arms anyway, I would highly recommend doing the Shelby Drop. You can get some great info on that here: http://home.bresnan.net/~dazed/drop If you do mods to the front suspension, especially installing those much stiffer springs, I would recommend a heavier front sway bar, and I would recommend an upgrade to your rear suspension also. If you are running a V8 up front, and you still have the old 7 1/4" rear end, you wil find eventually that your rear end won't hold up to that extra power, especially if it is the original one. I would also consider replacing the older, softer rear springs and new stiffer shocks.
I don't have a 66, but I do have a 68 that was a T-code and I did the V8 conversion to it, and those are the mods that I did to mine to compensate for the higher weight and horsepower increases. Good Luck with your mod.

You MUST get rid of that 4 lug rear end.  it will break on you in the middle of the highway and the car won't roll and you will get hit.  Ask me how I know this.

Also, ditch the six cylinder steering linkage.  Bumpsteer with V8 spindles will be so extreme you won't want to drive the car.  Includes pitman arm, idler arm, center link, adjusting sleeves and inner/outer tie rods.

You may find that your 1" lowering springs with 620 pound rate do not actually lower the car from stock.  See my RIDE HEIGHT page to get a visual on what different springs and mods look like once completed.  I would definitely relocate the upper control arm mounting holes to 1" lower.  Daze has a good template and drill bit set he sells, or you can find the dimensions easily with a google search.  Tony Branda has a good drawing.

My 1966 Gt rear springs,GT front springs with shelby drop on front.289 V8 with 15" wheels like yours.
Mike

On your ca you go new csrp disc brake swap you swaped spindles to though correct i6 spindles for 65-66 are different then the v8

True74yamaha wrote:

You may want to pull an explorer rear end and shorten for your car. That way you'll even have disc brakes in the rear end and a pretty strong one two

+1 to this too!  I just did that swap at the end of last summer.  Love the discs and the 31 spline axles.  E-Brake is going to be a pain though.

I did the Shelby drop on my 66 also converted from I6 to V8. I'm running 620 springs with grab a trac 4 leafs out back and 1" lowering blocks.

I like the idea of using the 6-cylinder springs and using a stiffer shock with the 1" sway bar + export bar +monte carlo bar. Should be juuuust right and handle like...."somebody elses car!"
6s6

mjacobs wrote:

Would it be advicesable to install old V8 front coil springs as apposed to using new 620lb springs?
thanks again

No not the original springs. I would get new stock springs and cut them to get the ride height you want and a slightly stiffer spring.