What size truck would you recommend for towing a 36 Spectre cat on a triple axle trailer? A 1500 Dodge with a hemi wouldn't cut it, right?

I think it would IF you

1) Upgrade the shocks and use a helper spring

2) Upgrade your front brakes at least

3) Go to a Class IV hitch

4) Do some engine mods-air filter, chip etc

5) The transmission is the weak link in that powertrain. Change to a stronger billet torque converter.

6. Change all fluids to synthetic if they're not already.

You can do all this and still not have enough truck,or you can buy a F350 and be done with it.

A boat of that size and weight requires a 3/4 ton minimum for safe towing. Don't kid yourself by thinking that strengthening the drive train and going to synthetic fluids will change things. The frame, axles etc. on a 1/2 ton just aren't strong enough and will flex under the stress of the load leading to poor handling loss of control. I trailered my Formula 271 (7,000 lbs. on trailer with gear) for years with 1/2 ton Suburban and while it did just fine I noticed a world of difference when I went to the 3/4 ton configuration.

Nevermind the Hemi isn't strong down low, but a 1500 is not near up to the task of safely towing a 36ft Spectre... you'd be white knuckling it.

No way. You want a dually anyhow towing a big cat.