M-20 decoding questions - Page 2

**YENKO DEUCE REGISTRY** · #11 07-17-2002, 08:05 PM

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** · #12 07-17-2002, 10:25 PM

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 · #13 07-17-2002, 11:07 PM

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** · #14 07-18-2002, 01:28 AM

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 · #15 07-18-2002, 03:39 AM

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** · #16 07-19-2002, 01:22 AM

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 · #17 07-19-2002, 02:01 AM

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** · #18 07-21-2002, 06:26 AM

Up to you, build up the 350 or get a 400. Not that big of difference, esp since you already have the 350. [img]/ubbthreads/images/icons/smile.gif[/img] 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 · #19 07-21-2002, 04:35 PM

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?

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