alright so i know that in the years 85 to 86 chevy changed the cams in the iroc 305 engine which gave less horsepower... my question is what type of cam was in the 85 model (be specific) and can i put that in my 86 to get the lost horsepower back?

along with this information i also need to know what the origional size the wheels were. i have 15" wheels and i know that's not the right size cus its messing up my speedometer.

 

well most likely your 15 inch wheels are either factory and your speedo is correct or your speedo isnt correct if you look up your RPO codes you can find out if the wheels were 15in from factory your RPO codes are located in the center console for your year i believe

 

The outer diameter of the factory 15" wheel tire combo, and the OD of the 16" wheel/tire one, are within about ¼" of each other.

So if your speedo is off, something else is causing it.... off-the-wall tire size, gear's been changed, etc.

The 85 cam was the same as the L69 cam, the 86 cam was the "peanut" cam.

No one in his right mind would take out one lame stock cam and put another maybe barely slightly almost a little bit less lame stock cam in in its place. That's just crazy talk.

If you're going to go to all that trouble, put something decent in it instead.

 

i bought the car with wheels that i know are not from the factory. they're some getto looking things i'm trying to get rid of i found a guy that i think will trade me for the origional wheels though. ok so if that doesn't fix my speedometer then i think its the speedo cable. which i have i've just failed to put it on yet due the lack of knowledge of what i'm getting myself into.

is the instalation of the cable pretty simple or do i need to know something before i just start pulling the gauge cluster out?

so what would yall suggest on the type of cam i put in? i'm not willing to go and buy a super expensive cam so if yall give suggestions i kidna need to know the price of them or an estimate of the price

 

Sofakingdom had just put this info in another thread where someone asked for a camshaft suggestion for a 305;
the compxe256. The xe262 is a little more top heavy, if that's what you're going for.

The speedo cable will either work, or it won't, it won't slow anything down and make it misread (like read low).
Check the speedo gear in the tranny (drive, and driven).

I think the tires are what's causing it though, post up what tire size is on the car right now.

 

my tire size is 225/50 R15 they're pretty dang wide. and i just had a whole tranny rebuilt everybit of it for 2000$ its not that gear (it better not be for 2000)
these tires are on 15 in rims that are not the factory wheels

 

ok, the wheels don't matter, but that size does. It's a bit short.

215/65/R15 is your stock size I think for that year.

The drive gear in the tranny could be whatever they put back in it, and the driven gear (the easy one to get to) is probably the factory one still. You can probably get a different driven gear to set the speedo right (or close enough), or get the right size tires. The driven gear is $10 from GM.

How far off is the speedo now?
I made this excel spreadsheet before, you might be able to use it to confirm how far off your speedo is, and what you can do to correct it.

 

my speedo is about 10 mph off. i'm trying to get ahold on some whole new wheels and tires i just bought another camaro (parts car) and i think i'm gonna try to steal them off it. i'll look into the whole "driven gear" thing though...