Rear axel check strap bolt size and exhaust

[Green Hornet 88]

Hey folks after the galvanizing the chassis of my series 88" I need to tap out the bolt holes for the axel check straps .  I tried to measure them I believe they could be 3/8ths UNF or  maybe 10mm UNF ?  Does anyone know the bolt size?
Also I have a few exhaust from, I believe the original gas engine?  I now have 2.5 NA diesel can I use the gas exhaust with diesel if it fits?
thanks folks
Cheers

[binch]

According to the parts manual showing the chassis the bolt is  part number SH606081L Set Screw 3/8 Unf x 1 Inch. (hex head bolt)

https://www.johncraddockltd.co.uk/other/military/parts/hardware-and-fixings/sh606081l-set-screw-38-unf-x-1-inch.html

;)

[camo388]

From what research I did, using the gas exhaust pipe will work OK and probably less work to fit.  You will need to use gas engine manifold so you can keep down pipe that matches the rest of the gas exhaust pipe work.  If you keep diesel engine manifold then you would need to reduce that down pipe to match gas exhaust.  I don't recall the exhaust pipe size difference but not a lot.  If you want to be technical, the diesel engine should use it's designed pipe size for maximum performance, but hey it is basically a farm tractor engine not an Indy racer. 

[binch]

I would have thought the diesel would breath better with the larger exhaust on the 2.5na.   When you only have 68hp why rob it of a couple more?    I would keep the parts consistent with the engine personally. ;)

[camo388]

I whole heartily agree with you Bill.  In this case bigger is better.  However the 2.25 gas exhaust system will work and it is only a matter of changing exhaust manifold so down pipe just bolts right up.  Or he can use 2.5 manifold and modify 2.5 down pipe to fit to rest of 2.25 exhaust system.  It is 6 of one and 1/2 dozen of the other if he wants to use as much of 2.25 exhaust and therefor have the truck on the road sooner.  If he wants all 2.5 exhaust, (which is better for engine performance), then even if he got a 90 system from the Med Hat wreckers, he would have to cut and weld to fit, so a longer job.  He also has to be aware that there are 2 down pipe styles on the 2.5 and not interchangeable so check which his manifold is before getting down pipe.  One style has a bell end and the other is straight pipe with stopper ring that is inserted into the manifold.