Help me decide if I should build a frankentractor

Hello men, currently have a wd with a 45 crank and 4.125 overbore kit in it. Does pretty good for our small time outfit but as always I’m looking for more lol. In my research it seems that a d17 block offers better oiling and a stronger block overall. This tractor also has the straight stick transmission in it. Also in my reading it seems the curved shifter transmission in the late wd or 45s are stronger. I would like to put a stroker crank in this tractor. Talking with Dan carpel it seems 5.5 inch crank is doable with his billet rods being used.
My question is will the block hold up long term with the crank in it, is there any supporting modifications that can be made to the w201 block I currently have or is it better off with the g226 of a d17? Also would it be worth it to wd45 swap the rear section of the tractor for the stronger unit with slightly slower gearing.

Tractor currently runs in a 2.5 mph class close to home with 3.0 mph being the speed of some pulls we travel to. I can run in a 5mph class close to home but I have nowhere near enough power to do that currently. The d17 engine is an approved repower for the clubs I run

You are using low gear now, which is 2.5 MPH. Changing to a WD45 trans/rear end will slow down low gear to 2.3 MPH. Nothing positive about that. The stock D-17 engine with M-code compression only makes 5 more HP @ 1400 RPM over a STOCK WD45 engine, because of an increase in compression. If you currently have 4 1/8" pistons that have 140 or more PSI cranking compression, you won't have ANY more HP @ 1400 RPM from a stock D-17 engine, probably less !!!! Exactly how much compression you have now has to be matched (and same bore) in a D-17 engine to have the exact same HP at the same 1400 rated load RPM's. So, to go forward with any changes you must determine what compression you currently have in your WD45 power plant.  I'm not sure of your goals. I belong to a club that has "stock" classes, in which there are several WD45's that pull in low gear with 13.6 x 38 non cut rear tires and are quite dominant. They run 4,000-4,500 and sometimes 5,000 lbs BUT, their drawbar rules are 16 inches high and 14 inches longer than the end of the PTO  shaft. That is a "stock" dimension drawbar. The same club has "Antique" classes with a 4MPH speed limit and the typical 20 inch tall x 18 inch short drawbar. I can tell you that 4500 and 5000 lbs with cut 15.5 x 38's require 100 or more HP to be really competitive and be able to run 2nd gear with a  WD45 DIESEL rear end, which is a 15% slower ring and pinion.

Edited by DrAllis - 14 Feb 2023 at 8:14am

The 2.5 and 2.3 MPH rating are with standard sized tires 13.6 x 28's at 1400 RPM's. ..    2.5 MPH turns into 3.3 MPH with 18.4 x 34's.    2.3 MPH becomes 3.0 MPH with 18.4 x 34's both at 1400 RPM.  So, going to an 18.4 x 34 is about a 30% speed increase, let alone a traction increase, which requires more torque from the engine to spin her out.

Edited by DrAllis - 15 Feb 2023 at 7:43am

Find a shorter wider set of tires that you DO have the power for. TALL tires DO NEED big power. Find the perfect match tire for whatever gear you can run and you'll do better than someone with tall tires without the power to turn them.