C2 Pitman Arms part # difference for Non Power Steering

[Gary J.]

[Alan D.]

Re: C2 Pittman Arms part # difference for Non Power Steering

Gary,
71 P&A shows for 63-72 corvette .... 3741383 for PS and 3829451 for exc. PS
perhaps the 3829452 is the casting number? My car has the 3829451 on it (original 1964 manual steering)

[Joe L.]

Re: C2 Pittman Arms part # difference for Non Power Steering

What difference is the between Pittman Arm part #3829451 and 3829452 for a non power steering car? In the ‘67 Judging Manual it says that the 3829452 is used. Is part #3829451 used and if so for what years? Is there any physical differences between the two?

Gary------


I can find no record of GM #3829452 having ever existed as a finished part number. It is possible that it was once an alternate forging number for the 3829451 finished part number but that's just speculation. The only part number for the 1963+ Corvette with standard steering pitman arm was 3829451. Personally, I've never even seen a pitman arm with the 3829452 forging number.

[Gary J.]

[Joe R.]

Re: C2 Pittman Arms part # difference for Non Power Steering

Gary,

Yes, there are physical differences as the arm for PS arm drops down a few more degrees to miss the PS Cylinder. I have put PS on a non PS 63 without changing the arm BUT there is not much clearance.

JR

[Joe L.]

Re: C2 Pittman Arms part # difference for Non Power Steering

Ok my mistake, the ‘67 judging manual says forging number 3829452. So will the Pittman arm have both numbers, the part and the forging number on it?

Gary------

As I mentioned, I've never seen one with a 3829452 forging number but that does not mean they don't exist. It would fall into a common GM pattern, though. Often times, forging/casting numbers will be one digit higher than the finished part number. In this case, though, the forging number is usually, if not always, the same.

Power steering cars use a different pitman arm with a completely different forging number. It was GM #3741383 which was both the forging number and finished part number.

By the way, the standard steering pitman arm, GM #3829451, was unique to Corvette applications. The power steering pitman arm, GM #3741383, was also used for many 1958-64 passenger cars.

[Mark F.]

Re: C2 Pittman Arms part # difference for Non Power Steering

The link below also discusses these two parts; their applications; and their date ranges.
It shows two views of both parts, including the dip that Joe Ray mentions above.

https://www.corvetteforum.com/forums...hard-left.html

Were these parts cast and then forged internally by GM? or were they outsourced?
Do we know if they were drop forged in open dies? or, were they hydraulically/mechanically compressed (forged) in closed dies?

Drop forging is a very interesting process to watch - LOUD; vibrates everything in you (and around you); and you better not get in the way
all very interesting stuff, eh?

[Joe L.]

Re: C2 Pittman Arms part # difference for Non Power Steering

The link below also discusses these two parts; their applications; and their date ranges.
It shows two views of both parts, including the dip that Joe Ray mentions above.

https://www.corvetteforum.com/forums...hard-left.html

Were these parts cast and then forged internally by GM? or were they outsourced?
Do we know if they were drop forged in open dies? or, were they hydraulically/mechanically compressed (forged) in closed dies?

Drop forging is a very interesting process to watch - LOUD; vibrates everything in you (and around you); and you better not get in the way
all very interesting stuff, eh?

Mark------


You will note that most, if not all, of these pitman arms, standard and power, have the mebossment "GMT". The "T" refers to the GM Tonawanda forge. I do not know what process was used there for these arms but I highly expect it was NOT drop forging.

[Mark F.]

Re: C2 Pittman Arms part # difference for Non Power Steering

Good deal, Joe - and I should have picked up on that "GMT165" in the one photo...

Well, if it wasn't drop forging, whatever process was used (closed-die forging?) it sure had to be fairly efficient as I suspect many 100's of thousands of pitman arms were forged over the years at Tonowanda.

thx, Mark

[David L.]

Re: C2 Pittman Arms part # difference for Non Power Steering

My 1967 Chevrolet Parts Catalog (July 1967) lists GM # 3829451 for 63-67 CORVETTES (exc. P/S) and described as "(forged 3829451)" and GM # 3741383 for 63-67 CORVETTES w/P/S and described as "(forged 3741383)".
Dave