I was wondering what the stock specs on a 86 305 TPI cam are. Or if anybody can tell me if I need I to change the valve springs, when putting a .480 lift cam in that engine. Also does anyobdy have any suggestions on what kind of cam to get
thanks,

 

.404/.415 was the cam specs on the 85 Iroc-Z.
Yes you will have to mod your springs for that cam. In my opinion that is going to be way to big of a cam. The 305 needs low end since it is lacking in cubes and bottom end. I would go with a cam no bigger than a .440/.454 unless you have some good mods in it. What kind of induction do you have or are you using?
The springs in my 85 are from a L98 Vette. They work great and were cheap to boot.

 

That ".480" lift cam will turn your engine into a slug. Your TPI intake will not match the cams characteristics, and HP, torque, driveability and emissions will suffer.

Instead, consider a cam designed for your application. Crane makes a nice piece, Crane PN 114132. Its a hyd flat tappet, and specs at .440/.454 lift and 210*/216* dur. Powerband is 2000-5000, which matches the intake quite well. Power should increase significantly, at least 40HP or so. Maybe more if you have other bolt ons. New springs are highly recommended.

Your stock cam specs at .350/.385 lift and 179*/194* dur. Really pathetic. Often referred to as the peanut cam. Probably the mildest SBC ever offered.

 

He has a 85 Model. The 86+ were the Peanut camed LB9's. The 85 like mine is the 215HP 275lbs/ft. 86 offered good torque 285lbs/ft but the "peanut" cam got it only 190hp. Yeah really pathetic.

 

How do you know that? He is asking for 86 specs...

 

Could have swarn I saw that he said he had a 85. Oh well carry on. Sorry I got the wrong year then. LoL maybe I was drunk.

 

why is that? would putting the cam in my car that have..have made my car a slug?..ima just a wondering....going to have it dyno'ed this week and see.

 

I'm pretty sure its the generic grind that nearly every cam manufacturer offers: .480" lift and 230* dur @ .050" single pattern cam. That cams powerband is way out of your TPI intakes powerband. The long tube runners of the TPI were originally intended to make good low end torque, and they do, but at the same time they hurt higher RPM HP. By the time the cam begins to make good power, the TPI is all done. The TPI in stock form moderately reduces power potential above 4500rpm, and absolutely kills it above 4800-5000rpm. The single pattern cam is better used in an engine with more efficient heads and a good dual exhaust than what your car has. It will also hurt low end torque, which is where your car shines. The entire FI setup isn't exactly friendly with the 110*LSA of that cam either.

In addition: That cam will perform miserably with 2.73 gears and a stock torque converter. It would like a torque converter stall around 1000rpm higher than stock, 2400-2600 would do, along with at least 3.42 or 3.73 gears.

Instead, look for a dual pattern cam with 112-114* LSA, .050" duration under 220*, and lift not too much over .460 for your combo. That cam I mentioned is perfectly suited to your engine. It was designed with your engine in mind

 

I have 3.73's and a 2400 stahl torque converter, and a borla catback. I have decided to get vortec heads, will also be getting slp runners, 52mm throttle body, fuel pressure regulator, havent decided which intake manifold, and edle brock shorty headers. I was never planning on putting a .480 lift cam in a stock 305. So now after hearing the mods I want to do. Would a .480 lift cam still make my car a dog

 

correct me if im wrong but isnt scoggin dickey the only co. that make a tuned port manifold to fit vortech heads????

 

Your probably right, to tell you the I havent even looked in the what intake manifolds fit vortec heads

 

Well that's a different story. The gears and the converter help, and so do the TPI runners. SLP runners aren't the best. You can find better for the money. A good base would be crucial. And although the cam you're looking at would work well with the above components, I still recommend a dual pattern cam to aid in scavenging the exhaust due to the Vortec's weak exhaust port flow.

 

I was under the impression that slp runners were the best. Where could I find better ones?

 

Arizona Speed and Marine have better runners.
Arizona Speed and Marine

Since you have heads that big cam shouldn't hurt you at all plus you are gonna have runners to match it.
I am going to a bigger cam as we speak. I am getting the Crane Powermax Computer cam 114142 .454/.480. I just got my heads fully ported and polished with new everything. I am going to get the intake and runners ported as well as the base to see what happens. The cam may still be too big so I gotta port all the above things.
the Vortec base makes a huge difference over the stock piece. Go for it you'll be happy.