just having another brainfart....has anyone seen a 3306 engine in a larger dozer than a D6 or D7?  like a D8 etc?
-crank the fuel up, bigger turbo etc...could it accomplish the mission...?

Uh.....NO!

Rome K/G is right. The best I can describe putting a 3306 in a D8 would be "Like taking a knife to a gunfight!" lol!
Craig

Hi Team,
nearest I recall is Cat came out with a D333TA conversion for early 23H S/No 621 Scraper Tractors to replace the troublesome D336 engines they had from new.
It was expensive so several customers fitted Mack truck engines instead once they worked out how to drive the hydraulic pumps.

Our Dealer also purchased 2 late 17A D7's less the engines and fitted D326 engines that ran at higher speeds to compete with faster on the ground Allis Chalmers tractors of the day--somewhere I have some photos of the conversion in progress at the Dealer--may take some time to locate.
They were successful and one still exists but has been thru several hands with nothing being done despite me donating some D337 parts to it.--they were done for Telecom here our Australian Telco.

Plenty of 1670 and 1673 truck engines went into R190, R195 & R200 including 2 tilting cab over R200 Internationals, WW2 Macks, Albions and so on as big trucks were thin on the ground here in the 1960's.
Most of them were flat out with their ears back doing 50mph but the overall travel time reduced by half on some mountainous trips even when still using the old petrol engine boxes with big jumps that made the Cats lug up thru the gears--usually 1&2 close together and 3&4 close together with a big jump between 2nd and 3rd next was overdrive and two speed diffs helped--tandem drives had a Joey box with under drive, drive, and overdrive that helped some.
Customers with the fuel tanker runs to Cooma reported going from 2.5 to 3 mpg on petrol/gasoline to 12mpg on diesel they would meet other  competitors still heading to Cooma when returning for their next load.
As a 4th year apprentice it became my task to do at least 5 of these conversions at the Dealer as I had learned a lot of this stuff from working in my fathers business as a youngster on week ends and school holidays for pocket money before I even got to start my apprenticeship.
Better stop waffling.
Cheers,
Eddie B.

in my search i found a d6b i think that had a 1673 transplant.

Lots of 1673B and 1673C transplanted into 9U and D6B in the Palouse for farming. 3406 into D7 tractors but never around one that had a smaller motor transplanted. Mike

thanks for the feedback and interesting stories...

-i don't think it requires 1200+ cubic inches to make 300HP though...not nowadays anyhoo...and a 3306 (10.5 Litres)(638cid) is definitely on the short side for longevity and ease..
-has anyone seen a 855 Cummins (14 Litres) in a D8 or D9?

-please forgive me if this seems blasphemy..

20.4 liter D342 in D8H, D8K & 18 liter 3408 in D8L would be more than a 14 liter N855 would handle, these tractors need a large amount of metal flying around to drive them, the torque required is more than many of these little engines can match. One has to consider gearing and revs to match being another issue, smaller engines just don't produce the HP at the lower revs to match the gearing.

Wombat