I was looking around here http://www.iroczone.com/techartspottersguide.html
and found that this says that my 87 IROC is supposed to have an 85 mph speedometer because it is a Carbed 305 but mine has the 140mph one
How do i figure out what was changed to make this happen - whether it was the speedo or the manifold or the whole engine?

 

Probably the speedo.

It costs alot less to buy it by itself, than to buy the speedo AND an engine or whatever.

Takes a good solid 5 minutes to swap it out, if you're slow like me, and you stop twice or maybe 3 times for cold ones during the process and consume them in their entirety.

 

when I first bought my formula it had a 160 mph speedometer. I was like WTF they do not even make one for this car, but then I found out it was just an overlay they put over the gauge. It is really a 140 but they printed a paper out and glues it over it to say 160.

 

The paper over the speedo thing is quite possibly the stupidist thing ive ever heard of. How do i tell if the engine is the original to the car. I know there is a way to do this with the VIN but im not sure what im looking for to tell if its the correct engine by looking at the engine block. Sorry a little slow i guess.
thanks for the feedback i did get

 

What does the originality of the engine have to do with whether somebody swapped out the speedo?

My 83 car has a 145 mph speedo in it, too; didn't come that way; but there's no connection whatsoever between that, and what engine is, was, or ever will be in it.

 

heres a good site to ID vin codes:

http://www.chevy-camaro.com/chevy-camaro-VIN-decode.asp

 

How so?

I've heard some REALLY STUPID stuff before. That doesn't even come close. It's pretty common, in fact; white face overlays for example are popular for these cars.

 

Hmmm.... that was weird..

 

Yeah but one that is 20mph over the actual speedometer with out recalibrating it is done for what reason other than the person was a complete idiot. Anyway i blew the head gasket on the 305 yesterday so instead of wasting the time to tear it down im just gonna drop in a 350. If anyone has one they are gettin rid of cheap let me know.
Thanks for the help anyway guys im sure ill have plenty of questions in the near future

 

That's just it...

No recalibrating is necessary.

If you have the 85 mph speedo, the pointer travels through some specific angle going from 0 to whatever; let's say, at a guess, that it moves 1° per mph. 60° = 60 mph. 85° = 85 mph.

If you have the 145 mph speedo, the pointer still moves THE EXACT SAME AMOUNT; it moves 1° per mph (or whatever the actual value is). All that changes, is that now there's 145° of markings. The markings on the scale don't have SQUAT to do with that. 0-30, 0-60, 0-90, etc. are all THE EXACT SAME AMOUNT of pointer movement, REGARDLESS of the full-scale value that it can indicate.

You should actually make an effort to understand what you're talking about, maybe even just TAKE A LOOK at the 2 objects sitting side by side, before calling other people names.

What makes you think you blew a head gasket?

 

Well i guess once again it has been proven that i open my mouth before thinking Thanks for taking the time to teach me something.

Oh and the head gasket - well i was running it hard and it started to over heat so i parked for a while to cool then checked the fluids and they were low but still acceptable so i went out again and noticed that i had a lot of white smoke coming from the pipes and it started to overheat again but this time it was really fast. I thought it might be a head gasket so i called my uncle who owns a shop and is an ASE Certified Master Technician and he confirmed that a head gasket was most likely my culprit. Ive kinda been wanting a little more motor anyway so i might as well put a 350 in it and rebuild the 305 as a backup motor since the opportunity for major surgery has presented itself.

 

You and me both... I'm as guilty as anybody. Oh well, as they say, you live and you learn, or you don't live long. Eh?

A head gasket is a possibility; but I'd suggest a compression check before tearing all into it.

 

Yeah i do need to do one of those but its gonna have to wait till i can put this bad boy on the trailer and get it down to the shop where i have the proper tools at my disposal and a roof over my head so im not so freaking cold.

Is it possible im just looking for an excuse to swap the engines?

 

That's what I do. It is like that "sears" commercial when some guy put like a circular saw and leaf blower behind his wife's mini van and said "oh well guess we have to go to sears."

I blow up motors to make excuses to get bigger ones :P

 

i love that commercial!
Hmmm that gives me an IDEA!!!! I need a laptop too. LMAO