May want to consider sealing the tank yourself with the POR-15 Fuel Tank Repair kit. Just did this on my 77, and was surprised at how easily it was. As long as you're dropping the tank and flushing, you might as well go the extra mile and take measures to ensure you won't have to do it for a long time. Gas Tank Renu quoted me around $325 for a renew job. I got it done for around $50 with the POR kit, along with about 3 hours of flushing, prep, and coating. Wait-time for the POR coating to cure is 96 hours. Wait time I was quoted for the Gas Tank Renu was 2-3 weeks. If you have access to compressed air, you won't have to worry about clogging your pickup & vent lines. Good luck!!