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Old September 28th, 2023, 03:06 PM
Prowbar Prowbar is offline
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Join Date: Dec 2020
Location: Friesland, the Netherlands
Truck: 1965 GMC 1500, 478 V6, SM420
Posts: 386
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Prowbar is a jewel in the roughProwbar is a jewel in the roughProwbar is a jewel in the roughProwbar is a jewel in the roughProwbar is a jewel in the roughProwbar is a jewel in the rough
Default Re: '65 GMC 1500 project. From the Netherlands

Thanks for the compliment, Steve.

Indeed, as you said, the synchros were still good, but the wear cannot really be detected other than the "points" of the internal thread in the synchros getting duller, thereby needing more effort to cut through the oil layer on the cone. I have noticed improved shifting times, but this can also be psychological rather than factual.

Ended up ordering the kit from Transmission Parts Distributors in NJ. I ordered from them since they shipped worldwide and had the synchro's. Didn't contact Novak, I contacted them in the past but never got a reply. If I were to do it again I would order the Ebay rebuild kit. Saves a lot of money. I believe all the kits are the same, and the 63 and earlier transmissions seem to have a different front secondary shaft roller bearing. I got 2 bearings in the kit that I did not use.

I did notice that the input shaft bearing in the kit is a C3 style bearing, which is normally only used for 2 press fits (shaft and hub). These have greater internal clearance. Possibly selected for misalignment purposes? The trans has a press fit on the shaft and a loose fit in the case, therefore not needing a C3 bearing.
Anyway, the original New Departure bearing was also of the reinforced type with more ***** and a filling slot to accommodate. The new bearing is just a standard-size bearing, with a standard amount of *****.

I wouldn't be surprised if Novak just splits up the kits with the right parts for the transmission year.

As for the A/F, I am running just below Stochiometric at cruise on propane (around 14.5-15.0, Propane is around 15.2-15.5 AFR stoichiometric) and it runs really well. Idle it set to about 13.5. Haven't had any problems with a lean condition problem (no surges, just constant power @ cruise) so far. This might be because of the propane. Gasoline is kept as a backup only. Indeed, I have an AFR on the driver's side exhaust but could also tap into the passenger side exhaust, have a bung on it as well but it is plugged off now.

I like to tinker around but also try to listen to good advice... it is a fine line for sure.

Last edited by Prowbar; September 28th, 2023 at 03:53 PM. Reason: for some reason it sees b@lls as a bad word :)
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