International D1510 diff help

Hey guys need some help, i have a 1973 inter D1510, 5 stud 16" wheels, previous owner has fitted a perkins 6.354 diesel and a 4 speed, the problem is it still has a petrol diff and is flat fart at 70kmh, so i need to upgrade the diff, any one know what diff i need to bring the speed up to something respectable? Thanks

If earlier models are any guide, it has a 4.88. (may be 6.16 if it had 20" wheels when new) Fastest ratio was 4.3 on that axle. (ISTBC)
20" wheels will help. I think it would have had 17's when new, 16's probably from Dodge.

Best you check what centre it has now. Should be stamped in casing above the yoke, otherwise the wheel test.

Jarrod.

Thanks Jarrod, currently it has 16" on the front and 17" on the rear but different tyre profiles even them out. Hoping to get at least 90kmh out of it. I will do a ratio test and see what happens. Do you know what breed the diff would be or are they an inter? Thought about putting a jap diff under it?

totally agree for your situation tyre size will be the cheapest and easiest, not 100% on the legalities though. But for example going from 8.25R16 (assuming 34") to 9.00R20 (assuming 40") is equivalent to a 0.85 overdrive. IMO they look wrong with anything smaller than 20" rims too :evil:

Going up to the 7.50x20 tyres would be a legal no-no unless the rear brakes were upgraded too.
14.125"×3" drums for 17" tyres
15"×4" drums for 20" tyres.
Both had RA20 spec axle but 4.30 for smaller tyres, 4.88 for larger.

mad_as_hec wrote: Going up to the 7.50x20 tyres would be a legal no-no unless the rear brakes were upgraded too.
14.125"×3" drums for 17" tyres
15"×4" drums for 20" tyres.
Both had RA20 spec axle but 4.30 for smaller tyres, 4.88 for larger.

So could you put the bigger brakes on the 4.3 axle or could put the 4.3 center in the 4.88 ???? and what about the front end do the brakes change with 20 inch wheels ????

Paul

By the time you bought new axle/diff, wheels and tyres you could get a quick fit 6 speed (5 plus overdrive) box out of a 60's Commer and probably others - Inter, Dodge, Bedford??. Will just bolt up to the 6/354 and a very nice synchro box to use.

Lang

Interesting about the brakes. IIRC, an AB150 had the same brakes, whether 17, or 20" wheels. I'll have to go through the later books and do some learning!

Jarrod.

Hello Hemi & fellow readers, I can not resist the opportunity to point out that I have advertised a 4.3 diff and other parts on this site back at the beginning of October, it may help! Most parts have come off the D1510 pictured.
Apologies in advance if I have over stepped the protocols of this forum

Cheers Inter van man