Since you guys are already on the subject can I throw out a similar question?

I also have a '65 289 block and am soon going to change out my GT40 heads for a set of AFR165's. Personally, I wouldn't know what to do with a length checker if I had one so I too have the same question. Yes, I've heard the comments prior to my question so I know I'm stumbling into a can 'o worms but I thought I'd just ask.

If there isn't a "known length" for this application what is the process for finding out? What I mean is: How do they work?

Thanks!

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'65 Falcon Futura (weekend cruiser) Built 289, C4, TCI Street Master 3000 stall narrowed 9-inch and 4 wheel disc brakes. It's not a race car but its raced (a little) and its not a show car but we show it.