Trying to get rough performance specs on an engine from description alone

[SavageTitan]

Hi I'm new got a couple of questions.  My questions are purely for my own edification.  Many years ago I drove a double stick daycab straight truck.  Said vehicle was long had a 3 PC driveshaft, walking beam suspension, a steering damper shock, it had a 4k gallon water tank with a trash pump to siphon load when top loading wasn't possible.  I remember the engine was a Thermodyne 600, it was big and either teal or turquoise color to it.  The trans being a 2 stick had a 5 speed main, the other stick was kind if a menu: high or low forward or reverse - I think it was called a Brownie?  I never got that to split between high and low no matter what I did.  I simply took off in one range or the other.  Top speed was about 54 mph.  Now the interior, hoola hoop steering wheel PTO throttle lock placed where your right knee was, every bump you couldn't see in advance - got you cracking your left hands knuckles on the wing window's handle, but the A/C worked!  My questions:  how big was this engine, how much HP did it make, and how the hell were you supposed to shift that trans???  Truck was a beast 3 point turns for just about every turn, it had super single steers,  the hood was too heavy for one person to lift it off - this coming from someone with enough backside to pull off extended hood Pete's with no problem.  The walking beam suspension was very cool helped support all that weight in turns off-road.  All in the truck was big, capable, uncomfortable, and had balls for days.  I believe truck to be a 1973 or slightly older, it was older than myself, hood and fenders all one piece steel with the bulldog for you to dangle from.  I would literally not fit inside that truck nowadays, at least not behind the wheel.  Any help with my questions I give you a thanks.

[Mark T]

Sounds like the truck had a six speed in it. You don't "split" shift them. With the 3 position lever in HI  you'd shift the other 5 position lever as a 5 speed. The "low" position was for crawl'n around in soft stuff with the 5 position lever in first. When the 3 position lever was in "reverse"  That was reverse and the 5 position lever allowed you to chose the speed you wanted to go backwards in.  Very unlikely that truck had a Thermodyne in it. Maybe a 237 or 300 ??? 

[JoeH]

The trans was 6 speeds forward, 5 speeds backwards.  Left stick is gears 1-5, right stick direct low reverse, like you said. Low just sets all the gears down one notch.  2nd becomes equivalent of 1st, 3rd equivalent to 2nd, etc.  Its just to give you a crawler gear.  You only use low range for 1st gear when you need to crawl.  Now the 5 speeds reverse... Fantastic feature.  You can put it in 3rd reverse and cruise over soft ground before the ground even knows you're on it.  Engine is probably a 283hp, with the engine mounted charge air cooler.  

[Joseph Cummings]

33 minutes ago, JoeH said:

The trans was 6 speeds forward, 5 speeds backwards.  Left stick is gears 1-5, right stick direct low reverse, like you said. Low just sets all the gears down one notch.  2nd becomes equivalent of 1st, 3rd equivalent to 2nd, etc.  Its just to give you a crawler gear.  You only use low range for 1st gear when you need to crawl.  Now the 5 speeds reverse... Fantastic feature.  You can put it in 3rd reverse and cruise over soft ground before the ground even knows you're on it.  Engine is probably a 283hp, with the engine mounted charge air cooler.  

5 PTO speeds too

[tjc transport]

and reverse top speed was almost equal to forward top speed too in 5th.

[Vladislav]

Did the truck have an off-set cab? I honestly can't imagine a full one part hood made of steel. DM or DMM or RD800 could have steel nose but the engine gets accessed through a baterfly hood shells. Unified fiberglass nose is a different story. And with super singles at the front it was the most probably DM or DMM model. But all this just my guesses.