I posed this question to a friend of mine who has been doing IFS conversions
for years. This is a synopsis of his answer:
If you are doing a subframe install, i.e., Camaro/Firebird clip, it's a good
idea to re-install the sheet metal before doing any final welding.
Especially if this is the first time you've done one. Stand back and see how
the wheel centers in the wheel well. If the IFS lowers the chassis to any
appreciable degree, the wheel may appear to be too far back. There's no
fixed amount, you just have to eyeball it to get it right. There are other
reasons for a trial fit too. If a one inch raising or lowering of the
subframe will prevent a collision of the steering box and radiator support,
for instance, this is the time to discover it! Also, on some trucks (notably
F100 F**D) the wheel centerline is an inch too far back, from the factory!
So to make it look right, you move it forward when the IFS is installed.
If installing a Fatman-type Mustang IFS the manufacturers instructions
should give you some guidance on placement of the crossmember for correct
wheel centering. On these, the wheel centerline is determined by the
positioning of the crossmember, but they always mark the centerline on the
shop floor, relative to the frame, to make double sure that nothing has
shifted before final welding is done.
In general their motto is, " measure twice (or 3 or 4 times), cut (or weld)
once". You can't be too careful. I have seen a truck with a botched
subframe - not from this shop, BTW - and it was really sad that all that
work was done with such a horrible result. It looked fine until the fenders
went back on, then it was painfully apparent that the wheels were a couple
of inches too far back.
Jack / Winter Park FL
-----Original Message-----
From: Robert Strickland <karbert1@gte.net>
To: oletrucks <oletrucks@autox.team.net>
Date: Tuesday, February 23, 1999 9:29 PM
Subject: [oletrucks] axle placement
>I have been told that when installing an IFS that one must shift the
>axle position relative to the straight axle centerline to have the front
>wheels line up in the wheel wells. Does anyone know which direction,
>and how much? I am hoping not to have to unstack every last piece of
>sheet metal that I have off the truck! I would really hate to have to
>weld this thing in more than once.
>
>Thanks,
>
>Bob Strickland
>1951 3100/Corvette
>
>oletrucks is devoted to Chevy and GM trucks built between 1941 and 1959
>
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