Motorsports harness filler wire

Would there be any adverse effects from using less expensive txl wire for harness filler wire rather than using tefzel wire for the filler, reson is trying to minimize the cost of building my harness for my twin turbo 489" bigblock chevy powered 69 Chevelle.

Any input would be greatly appreciated.

TXL should be fine since its temp rating is not far off most "mil-spec" wire, obviously you will need a smaller gauge so that the OD is similar. Dont use standard PVC wire though as it will melt below the DR25 shrink temperature.

Thanks I was thinking of using 22 or 24 ga txl for filler wire since my harness will be constructed of primarily 20ga tefzel wire.