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General Category => General Discussion => Topic started by: Oldrat on September 24, 2015, 01:36:22 PM

Title: Help with T3 heads
Post by: Oldrat on September 24, 2015, 01:36:22 PM

Would a head marked

13 02 21 60
     R5


Be a direct replacement for a head marked

13 02 21 60
     R12


Anyone know the difference or relevance of the R5 & R12 numbers

Many thanks

Brian

Title: Re: Help with T3 heads
Post by: Antietam Classic Cycle on September 24, 2015, 04:29:46 PM

If you could post some nice clear photos of them, that would help. Shots of the intake mounting, exhaust port, sparkplug area and combustion chamber area in particular.

Title: Re: Help with T3 heads
Post by: guzzisteve on September 24, 2015, 05:12:42 PM

I believe that the R # is a casting # as in which mold it came out of.

Title: Re: Help with T3 heads
Post by: Antietam Classic Cycle on September 24, 2015, 05:17:12 PM

I thought the R stood for "revisione", i.e. R5 would be the 5th revision of the mold using the same basic casting. <shrug>.

Title: Re: Help with T3 heads
Post by: guzzisteve on September 24, 2015, 06:55:00 PM

Think you are correct, been a long time since I looked into this. Just remember it was a casting code.

Title: Re: Help with T3 heads
Post by: Oldrat on September 25, 2015, 04:23:12 AM

Thanks gents, that makes a lot of sense.

Title: Re: Help with T3 heads
Post by: Antietam Classic Cycle on September 25, 2015, 08:29:51 AM

Quote from: Oldrat on September 25, 2015, 04:23:12 AM

Thanks gents, that makes a lot of sense.

Still doesn't answer your question though. Differences between an R5 and R12 could be fin shape near the plug, valve sizes, port diameter, diameter of the intake manifold bolt holes, etc.

Title: Re: Help with T3 heads
Post by: guzziownr on September 25, 2015, 01:10:37 PM

850 T3  build date March 1975:

(https://lh4.googleusercontent.com/-0Pm0lh09qh4/VgWNF5ZBsbI/AAAAAAAAA4k/HDtG36XGZx8/w779-h685-no/Left%2Bhead.jpg)
(https://lh3.googleusercontent.com/-EPh3EWaFysg/VgWNFEwDg3I/AAAAAAAAA4c/GU_BuaGU0bE/w817-h685-no/right%2Bhead.jpg)