WIth recent discussions showing a variance in the amount of firewall clearance to certain components, I'd like to know how much difference (in exact numbers if possible - asking a lot I know!) there is in the possible location of the front subframe. Those of you who have recently replaced the subframe bushings should have the best indication of the "adjustability" that exists.
Distributor-to-firewall clearance seems to be an important indicater as well. Any changes in room before and after subframe bushing replacement would be helpful too!
The reason behind this is that I have been using my '69 as a jig and had assumed that it was representative of most other FGF's in stance and subframe location. I have recently had cause to question that and am finding that my car may have more than the normal amount of clearance! TIA!
The 69 is a bigger car. If the car in question is not a factory resto then of course you can just recess that area. I have seen an F body w/a shaved firewall and they used a trimmed down torque converter inspection cover and recessed it into the firewall. It looked good. If you are desperate for another inch or so (on the car) then I have also seen guys shim the tranny up on the cross member and it will tilt the engine forward a little bit.
How much do YOU have, TOH? I dont have any exact numbers (like you asked for) but when I replaced mine, I would guess-timate that if i were to have it centered, so to speak, Id have been able to move it in any direction between 3/8-1/2".
I have had at least ten off. This is including 1st gen Camaros. The way I always do it is to use the 'F' dimension from the service manual as a front to back location. Then I find the centerline of the body and the centerline of the subframe. I line up the two centerlines and check dimension 'F' and lock it down.
For a clearance reference, I get about 3/8" to 1/2" clearance from an HEI to the firewall. This is the same for 67-69.
Right now I have an OHC engine in the car, so I can't measure for V-8 distributor clearance! And PLT1 brings up another possible variable, difference in the compression or position of the various mounts.
Tom, is there somewhere that I can access those numbers on the net?
CDjr, so does that mean a total max difference of 1 inch between possible fore/aft locations?
Thanks, Jim, that's a good start! Vikki's numbers indicated that one of her cars' subframes could be shifted rearwards by the amount that CDjr stated.
Had I known that there would be that much difference in the cars as they came off the assembly line, I would have loosened my subframe and shuffled it back to give the least amount of clearance possible before starting fabrication!
I'll agree with Jim on the "firewall to HEI Cap" measurement, and also agree that very minimal crossmember shimming at the tranny mount point can increase that gap a great deal.
'68 428 HO M3 Monster, 4-on-the-floor! Need I say more?
Had I known that there would be that much difference in the cars as they came off the assembly line, I would have loosened my subframe and shuffled it back to give the least amount of clearance possible before starting fabrication!
What makes you think that there were variations as they came off the assembly line? It would be easy for them to get the subframe in the right spot.
Because of the claims that their car is untouched and perfect (okay not everybody thinks that) when clearance concerns arise. It's a lot easier to blame a new part than it is to adjust the car to fit!
I agree, Jim, there should been very little variation in the subframe placement at the factory, but I'm trying to nail down the actual state of things forty years later!
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