just thought i would share my experience with my gear change. i built a 92 d70 with a lock right locker and high capacity cover, POR 15 and clear coated it. when i was running 3.07 gears, boost was 40 psi with 1400 egt and acceration was very laggy and i needed 4 psi to run 60 mph on the freeway at 600 EGT. with the four ten gears i can run 60 mph at 4 psi with 560 EGT. at wide open throttle boost dropped back to a safe 30 psi and EGT max's out at 1000, acceleration is like a rocket now and the motor never sounds like its working hard to get the truck up to speed.

 

Whats your crusing RPM like and when do you top out now? Also what other mods?

 

dude i have 4:10 in my dually right now and i hate them they are only good when towing heavy and since dad retired and we shut down the buisness the heaviest i ever tow is a john deere tractor 70 mph is wound for sound and im thinking of looking for some thing in the 3:50 range i can live with slightly higher egts at cruise but i am very curious as you say 1400 max with 3:07 and only a 1000 with the 4:10 i understand the cruising speed egt but not max they should be a lot closer you still have the same amount of fuel at wide open your motor just revs out faster does it really cool off faster or am i missing something

 

because the stock converter is stalling out at 1700-2000 rpm its pretty tough to load up the motor without a trailer, on the freeway egt is 610, boost is 6 psi, and i am doing 60mph, remember i have 37" tires, my gps shows that my speedo is 5mph faster than what i am actually doing. rpm sounds like its 2000-2200, i have not used a full tank of fuel to get a mpg yet, ill let you know when i do. and with a trailer i was able to get 36 psi and 1200 on the egt. so about 220 degrees cooler at wot then with the 3.07 gears. i am callin spec right tomorrow to order a 1300 stall converter, or 1400, i know thats low but with the twins and 4.10's it should have no problem spinning it, and the tc loosen up over time so the 1300 will go longer before needing to be pulled and freshened up. thats the plan anyways.

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my bad, compound, not twins

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i will be towing my class 8 1967 ford desert truck on a 30' flat bed trailer and boats to the lake and what not,

 

I have had bolth and find that if you dont pull mountain hills and dont tow heavy loads ( 20000) plus the 355 work great. but if you push your truck like i do the only choice is 410s. just dont try and run the interstat at 70 mph with 410s, your engine and fuel milage will suffer. now the auto is another disussion.

 

i totally agree, where i live we have two of the steepest tows in america going up through sanora and tuwalami(sorry if i spell it wrong) county and what not.
on a side not do you guys agree with the 1300 stall? i know a518's cant run lower than a 1450? cause they get problems with getting tranny fluid to the overdrive, but i am going to be using a full built 727 so i would think the 1300 would be fine, probably a little tight but like i said, 4.10 gears, compound turbos, the torque made should be able to turn it no problem and i drive the freeway alot now because of my girlfriend so it should really help to lower the rpm's till i can save up for the gearvendors over/splitter. its expensive but i did the math and have seen the testimonials and it will pay itself off pretty fast. and with me getting my AA in welding soon ill probably be towing a welding rig all over.

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btw here is thwe quick way to install 4.10's
start by buying a 60/70 dana set with 4.10's in it, open them up and pull out the gear set and intall a locker,

then you re-install the set with a rock crawl cover

next you lift the truck up and pull out the 70 with 3.07 gears,

then you intall the new 70 and hook EVERYTHING back up and now you have a towing machine.

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all painted

 

Off topic but what's up with the crew cab chevy with the hood missing?

 

putting in a new 6.2 turbo detroit ha ha. the mother blew it up.

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the hoods to the left of my truck up against the wood stack

 

What about the front?

 

still waiting on the cross over high steer parts to show up so i can start the fab process.