front end rub problems

[dirtybird]

I purchased Hotchkis TVS kit with 3 inch drop springs for my 68 firebird. Engine is a 461 stroker with aluminum heads. When I called Hotchkis they said I need to use the small block springs part# 1937f. However, this is not working with my current wheel setup up front which is 235/40/18x8. Wheel backspace is 4.75. Any bump I go over it hits the fender. I know that many people run that combo, so I'm looking for advice on what you guys are doing to make this work. My thoughts are to either adjust my shocks (varishocks) to the stiffest setting, get 225 tires, or change to the Hotchkis big block springs which are only 2inch drop. My front suspension is otherwise stock. Any insight would be appreciated.

[Vicinity]

Isn't a 461 a BB? In that case, those springs you have are way to light. The aluminum heads will make the drop slightly less, IIRC, but wouldn't mean you need SB springs.

[dirtybird]

I thought the same, but Hotchkis recommends the small block springs for that engine. I think that may be the problem

[hifi875]

Is it a Chevy or Pontiac engine. Pontiac doesn't have big block. They are all classified the same

[dirtybird]

its a Pontiac engine

[exwestracer]

its a Pontiac engine

General (web) consensus is 575 for an all iron SBC, vs 600-650 for stock Pontiac (not sure why the range). With the alum. heads, you should be pretty close to the SBC. Question is: is the ride height what you want now, or are you just wanting to raise it to wherever the tires clear?

[MyFriendScott]

I use a 4 7/8 backspacing on my front 18x8 rim and run a 245/40/18 on it, no rubbing. I have just about 3" of drop. I do have to run about 1.5 degrees of camber to keep the tire out of the inner fender tho.

Switching your tire to a 225 will only help if the overall tire height is shorter, and even then, you'll only gain 1/2 the clearance of the overall height difference. The simple fix since you're most likely not going to have the rim machined down to increase the backspacing, is to throw a spring spacer (isolator) between the coil and the LCA spring pocket to raise the car.

[dirtybird]

General (web) consensus is 575 for an all iron SBC, vs 600-650 for stock Pontiac (not sure why the range). With the alum. heads, you should be pretty close to the SBC. Question is: is the ride height what you want now, or are you just wanting to raise it to wherever the tires clear?

I really like the look of the 3 inch drop, but I would raise it up an inch if it would make a difference. Will post up pics in a minute

[dirtybird]

I use a 4 7/8 backspacing on my front 18x8 rim and run a 245/40/18 on it, no rubbing. I have just about 3" of drop. I do have to run about 1.5 degrees of camber to keep the tire out of the inner fender tho.

Switching your tire to a 225 will only help if the overall tire height is shorter, and even then, you'll only gain 1/2 the clearance of the overall height difference. The simple fix since you're most likely not going to have the rim machined down to increase the backspacing, is to throw a spring spacer (isolator) between the coil and the LCA spring pocket to raise the car.
I have a spacer in there now, but I see that as a temporary fix. If I can't make the 3 inch drop springs work, then I will go with the bb springs I guess.

[dirtybird]

I do have to run about 1.5 degrees of camber to keep the tire out of the inner fender tho.

How did you do that?

[dirtybird]

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[exwestracer]

I think I'd work on the camber curve (which needs help anyway). The "G mod" or tall upper ball joints will help the top of the tire move IN under compression, so you might kill two birds (no pun intended) with one stone...without spending a ton of money.

[Smoker03]

I think I'd work on the camber curve (which needs help anyway). The "G mod" or tall upper ball joints will help the top of the tire move IN under compression, so you might kill two birds (no pun intended) with one stone...without spending a ton of money.

This is great advice to listen to. Having the camber curve corrected will help, but the 67/68 inner fender well can be massaged a little if needed as well. The 69 inner and outer fender have more room.

[MyFriendScott]

Yeah, I think the 67-68 Camaro inner fenders are different from the Firebird's so I may be getting away with a little more drop than you due to the difference in sheet metal. To add more static camber, you'll have to add more alignment shims between the upper control arm's cross bar and the control arm bracket. This will effectively pull the top of the tire inward. I should mention that I don't have a tall upper ball joint, but do have tubular control arms. With the control arms, camber settings, and lowered stance, the top of my wheel moves inward on compression rather than outward like a stock setup.

The car's looking great BTW. Love your rim choice. :)

[dirtybird]

Thnks for the advice guys. I will definitely start looking at the tall upper ball joints and/or G Mod