55.2-59 Big block clearance and cpp ifs coils too long?

[Spank-a-lank]

So Ive finally gotten my mustang 2 kit mocked up on my 58. I had ordered coils for a big block. well the coild are super tall and my control arms are stretched all the way it seems, leaving the ball joints at a bad angle. thought maybe the big block would weight it down but it did not do much. wondering if I should cut a coil out or find different springs. what length has anyone used with a big block.
Also...with the big block, I am running into some clearance issues. firewall being a major one. that and where the front of the oil pan wants to sit on the steering rack. may be able to alleviate that if I clearance the firewall enough. any ideas or photos of what you have done are helpfull. thanks much!

[dsraven]

if the springs are brand new they will, of course, sag some. what you wanna end up with is the lower control arms to be level with the ground at ride height.
sounds like what you are gonna be looking at is the firewall modification. wht I recommend to do is first cross brace the area, behind the firewall, in such as way as to support the area but not be in the way. the cut away the area in question. do your engine install and leave room for the oil pan and pulley/fan set up between the rad. then when all that is in and you have that completed, worry about the firewall. you could then fab something from scratch, use a modified steel wheel barrow tub or buy a recessed firewall kit.
without seeing your truck, I highly recommend to check the hinge pillars and cab mount areas before going too much further. sometimes the firewall is whats holding things together.

[Spank-a-lank]

so my lower control arms are nowhere ner level with the full weight of the engine and trans. I tried to attach photos but it wouldnt let me upload them. it seems waaaay off to me...they are even bowed out a little. I need to call cpp and see what they say. I ordered some original style short valve covers to see where I am going to need to modify the firewall. not a lot from the looks of it. may even be able to shave down the bellhousing mounts to drop the rear a little. id rather not cut on the firewall if I can help it.

[dsraven]

what I have done in the past is remove the springs and use threaded rod from the lower control arm to the upper spring "hat" to set the suspension at the desired ride height. usually the lower control arm is level at that height whick sorta sets the suspension in a neutral height. then when done do the trial and error method or get a used set of springs and modify till you get it right and then purchase a set of springs from the donor vehicle, or, if they are right, just paint them and continue.

[mr48chev]

You honestly won't know until you have all the weight of the finished vehicle setting on the tires after that first trip down the block and back.

Back in the day when guy were cutting MII front ends out of donor cars and using the whole thing many had to swap out the V8 springs for lighter springs as the weight distribution on a stock V8 MII A stock 75 MII V8 fastback weighed 2800 lbs with 60 % of the weight on the front end = 1680. Curb weight of a 56 3104 is 3360 with 1995 on the front and 1365 on the rear. Still the engine weight is centered several inches to the rear on the truck than it is on the stock MII.