Are my RPM's wrong ? At 4500 I'm doing 65-70.

Here's the deal, I have transplanted a 350 small block and turbo 350 transmission into a 1991 RS with a 3.23 rearend (according to the RPO codes). Using a Hurst swap kit to hook up all the linkage to the tranny and torque arm.
I have not connected my speedo yet. Because I still have to modify the bracket that holds the torque arm so the speed sensor can connect to the tranny. However cruising beside my wife in her vechile when she's traveling at 65. My rpm's say about 4500.
The small block easily is around 350hp,
and the turbo 350 has a 2100 stall converter.
The wheels are 15x7 with tires that are
215 on front and rear.

A little background on the 1991 RS.
It was a 3.1 V6 with a blown engine.
After reading that the V6 tach and V8 tachs are different , I purchased a gauge cluster off ebay. That was off a 1990 RS 305 according to the seller.

I feel like the cars in second instead of
3rd. but I check it every time to make sure.
Any ideas on what I can do.
I realize it is only a 3 speed, but 4500 at 65
seems obsurd.

 

That's not right.

Rent / borrow / buy some kind of test-equipment grade hand-held tach to compare your stock tach to. Stock ones are not instruments, they're a trim package, so don't expect accuracy. And, when they fail, they usually read high.

Of course you might find that your tach reads exactly (or nearly so) 33% higher than the test equipment grade one does; in which case it's probably about right, but you're just another victim of an "honest" e-bay seller selling garbage as a premium item to someone they thought they could take for a sucker.

You can probably tell, I don't buy much stuff off e-bay.

 

Your probably smart for not buying off ebay.
I usally try to stick to salvage yards myself,
but it was a case of a good deal (ha! or so I thought).

Thanks for the advice, RB83L69.
I'll try to get a aftermarket tach to check it with.

 

well what did the engine sounds like?
a high rpm would be louder than 2,000 rpm, your tach might be right and your tranny is still in a low gear for some reason...

 

The engine does sound like its higher than 2000 rpm on the highway.

I'm going to check the linkage this weekend.

I had a turbo 350 tranny in my old 86 Z28.
It had a factory stall (1600-1800) and it cruised at 65mph at about 2500 rpm's
with a 3:23 rearend.