1969 Ford F-250 with 429

Hi everyone - I have a 1969 F250 that my father put a 429 into back in 1970. The other thing he did was put 3.07 gears into a Dana 61 replacing the 4.10 stock gears. I have since put 33 inch tires on and have found that pulling my 6000 lb boat plus the weight of the truck and gear - puts me over 12,000 lbs. I have the cascades I pull over to go boating and am running around 1900 rpm (which feels a bit low). I need to change the gears and have the choice of 3.54, 3.73 or back to 4.10. RPM at 60 mph would be 2163, 2279, and 2505 respetively (http://www.csgnetwork.com/multirpmcalc.html) if this site is accurate?? Does anyone have the original stock torque and HP curves for the thunderjet engine? I also know my dad changed out the piston and rings to drop the compression ratio (I think to 8.5:1) due to lower octane fuel and detonation. Which would be the best gears to put in given my typical weight I'm pulling - while still trying to be semi conscious of fuel economy. I am leaning towards the 3.73's. What is the redline of this engine as well??

Thanks in advance!!

Karl

Welcome to the site . I cant answer ur question but Im sure you wont see the word " economy" very often around here.

an all stock older thunder jet would be good for 5000 rpm +/- Id be leary of the valve springs if they have never been replaced.

IMO either the 3.54's or 3.73's would be a great choice.

and like Dave C has said BBF's and fuel economy don't go together very well.

welcome to the site

Dave C. wrote:Welcome to the site . I cant answer ur question but Im sure you wont see the word " economy" very often around here.

Why, I always thought 2 gallons to the 1/4 mile wasn't too bad.  

HorsinAround wrote:

Dave C. wrote:Welcome to the site . I cant answer ur question but Im sure you wont see the word " economy" very often around here.

Why, I always thought 2 gallons to the 1/4 mile wasn't too bad.  

FPG not MPG....... Amount of Fun Per Gallon !