M-20 decoding questions

[69rsss350]

My 69 RS/SS 350 vin is 124379N671780 build date 08C
tranny # is P9H20A which would indicate a 6/20/69 build date for the M-20. Is it more likely that the "H" is correct or am I misreading what could be an "M" which would make the build date on the M-20 8/20/69. Is it common for the tranny to be approx. 2 months ahead of the cars build date? Casting # on tranny is 3925660, bell housing 389962. There are also some smaller vertical numbers aft of the larger P9H20A, what are these for? Thanks in advance!

[JChlupsa]

are the other numbers 19N671780 ??? if so its the org trannyt for your car.

[69rsss350]

Yes !!! those are the other smaller numbers! very clear to read. this car was sold to me as a numbers matching car two months ago, I believed the guy then but really didn't care cause the car is awesome. Would the Vin also be on the rear axle? I know it is date coded correct as H59 which translates to 8/05/69 another code I have found is BT which equals 3.55 posi. Right?

[JChlupsa]

H59 is Aug 5 1969 no VIN on the rear end but there should be a partial VIN like the one on the tranny on the engine itself. Either on the front engine pad to the front passenger side head or by the oil filter on the block . Also does your cowl tag show and X55 by chance. Also can you go to the Team Camaro pages also http://www.camaros.net/cgi-bin/forum/Ultimate.cgi and post all your info off the engine/tranny/cowl tag and rear end under the Tag team , so it can be recorded
Mahalo
section

[69rsss350]

Jeff, thanks so much...
cowl tag reads

Body by Fisher
ST6912437 nor103707 BDY
Tr 727 55B PNT
08C X11
General Motors Corporation
etc.

According to Camaro research Group X11 includes SS350

I will try to go to that site soon and enter this data. I know there are numbers on the engine block pad but I can't read them without pulling the alternator.

[Kurt S]

No need to post them there. This is good enough.
What's the rest of the BT____ axle code?
Shouldn't have to pull the alternator, just look from the side.

[69rsss350]

It gets stranger and stranger...
Numbers on block pad behind alternator read...
VO418TDR
C 87178681
apparently not the original engine but how do these numbers decode and what do they mean?
Rear axle:
axle casting date is H59
The (BT) I mentioned earlier turn out not to be BT at all but part of the test numbers, I was looking in the wrong place.
The numbers on the passenger side front are difficult to read but appear to be:
C BM 082061. It does have 12 bolts on the cover, haven't been inside the differential.
The casting numbers on the drivers side are:
3969341 NF. These numbers are very clear.
These don't match up with anything I have found on CRG site except the date code. Can anyone decode these numbers for me and give me an insight into just what these all mean?

[69rsss350]

Correction on the passenger side front of rear axle reads:
C BM 0820G1

[YENKO DEUCE REGISTRY]

I think the 3 letter designations for the engine and rear started in '70? I also thought that the engine application codes starting with T vs. C indicated a truck application?
The dates look good. /ubbthreads/images/icons/confused.gif

[Kurt S]

Yup, looks like a 72 truck block.
Rear looks correct, 3.31 open 12 bolt, dated Aug 20th. The C was added before the 2 letter code for the 1970 model year.

1 or 2 fuel lines?

Kurt

[YENKO DEUCE REGISTRY]

Kurt;
Is the C prefix on this rear end code indicating that it's for the '70 model year, or is it correct for this '69 car because it was built so late?
M

[Kurt S]

It's correct for the car since it's a late car. It's a 70 style code cause all the other car lines were 1970's already. The C is spaced off to the left and most people don't even notice it.
Also has a 1970 casting #.

Kurt

[69rsss350]

2 fuel lines, disc front brakes, has the brake switch ( not sure what it is called) below the drivers door underneath. I have figured out that the enginge code means flint plant 04/14 but don't know what the TDR or the year is or what the bottom line of numbers mean. I have decoded the rear end numbers to mean the dates are correct but didn't know what rear end ratio the BM indicated or whether it is positrac. What is with the casting numbers of 3969341 NF? Thanks for your help!

[Kurt S]

TDR is a 72 truck code w/ automatic.
The next row of #'s should be the partial VIN of the truck.
That's the casting # for a 12 bolt.

[69rsss350]

Speedo cable goes thru firewall to the left of the steering column when looking from front of car (towards passenger side of the column) wiring for back up lights and welds for RS headlight brackets appear factory correct. I have been told that by all indications this appears to be a original RS/SS with matching tranny and rear end, just a different engine block (which is not really surprising to me). Now my question is whether I want to drop a big block in it or not. This car is a consistent show winner including Saturday Special Achievment Award Street and Class Runner Up at the Super Chevy Show in Ennis (Dallas) Texas in 2000. I have taken it to two shows since I have owned it and taken home three trophys (2 1st in class and 1 best of show). I'm just thinking that since the engine isn't original anyway...why not go the big block route. I realize that I would probably have to change the tranny and gear ratio but can retain the original parts. Opinions?????

[Kurt S]

A nice SS350 with an NOM or convert it to a BB and have to change a whole bunch of things (heater box, engine and trans mounts, etc). I'd keep it more original. If you want more, put in a 400 SB.

[69rsss350]

Kurt, does it make more sense to put in the 400SB or build the NOM? Are there crate engine 400SB's available? If so what is the best place to get one? Will this be compatible with the M20? What about the rear end? Can I re-gear it and keep the rest of the rear axle. The NOM has edelbrock carb and intake. Please tell me what to look for and whether they would be compatible with the new 400. Thanks!

[Kurt S]

Up to you, build up the 350 or get a 400. Not that big of difference, esp since you already have the 350. /ubbthreads/images/icons/smile.gif Carb / intake needs would be determined by what you do with the engine.
Any SB will be compatible with the M20, just make sure the crank is machined for the input shaft.
Easy enough to change just the gears out. BTW, 3.31 / 3.55 are great all-around gears (acceleration and highway). I'd be looking more at adding a posi.....

[69rsss350]

As I understand it< I can add headers and still stay in street class at Super Chevy Shows, correct? Believe I will do that and add the posi first. Exactly what will that entail?