I have been doing some research to learn about camshafts. I have found many great articles in ChevyHighPerformance.com and CarCraft.com that teach about lift, duration, over lap and center-lines for flat tappet cams and roller cams.
I also read about flat-to-roller conversion kits.
The retrofit kits are very pricey and the roller cams are more expensive than flat tappet cams.

I was looking into upgrading my cam. I have an 85 T/A, TPI 305 with 700R4.
I don't understand why someone would pay that kind of money to upgrade to a roller cam unless there was some major improvements and benefits verses buying another flat tappet cam and new lifters.

Is there a reason I should invest into the conversion kit or should I buy a flat tappet cam and new lifters? I'm not building a race car, I just want a fun and quick street car.

Also, when upgrading a cam does the "lope" at idle come naturally or do I have to specify how much "lope" I want?
Does having a "lope" at idle increase performance or is it purely for show?

One more thing. Does anyone know the specs of a stock cam that's in my T/A? Then I can get an idea of what cam profile I want.

 

Stock Spec's 85 TPI
1985 (L69 and LB9)

Engine
305 AT

GM P/N
14088843

Lift
Int.
.403

Exh
.415

Duration
Int.
202

Exh
206

Lobe Separation
114.5

It is a decent cam from the factory. A cam change on an 85 TPI can be complex due to the computer in the car. Not easy to tune.

Just put some 1.6 rocker arms on it and a set of 3.73 gears, headers and enjoy our car.

 

Google
http://www.lunatipower.com/Tech/Cams...tOrRoller.aspx
http://www.badasscars.com/index.cfm/...100/prd100.htm
http://www.myrideisme.com/Blog/camsh...pet-vs-roller/

A roller cam has less friction ( less oil heat ) and for the same overall lift, and overall duration as a flat tappet cam ,
you can lift the valve quicker . More valve time open means better cylinder filling and more power.

"Lope" is a function of the cam specs ; the more duration ( overlap ) the cam has for top end use ( race motor )
the lumpier it is at idle
Lots of posers want their stock street engine to " sound" like it has a wicked cam in it

 

Yeah, too much duration or too narrow on an intake centerline angle on the cam will cause lots of "lope", or overlap, which will hurt emissions tests if you have those in your area, and lots of overlap also gives a stock computer major fits. My basic recommendation on cam specs for a 305 that you want to retain stock programming would be no higher than .450 advertised lobe lift, intake centerline, or LSA of 112 degrees or higher, and 280 advertised degrees or less of duration. In fact, if you really want to play it safe, 270 degrees advertised duration or less. You're right as far as converting to a roller cam setup. While they are nice, it's really not financially feasible for a simple street engine with a stock, flat-tappet cam setup. Comp Cam's High-Energy and Magnum series flat-tappet cams are good for a mild performance upgrade. Just make sure to choose one that's within the specs I mentioned above. If you want to go even cheaper, take a look at Summit's house brand, flat-tappet cams. Here's a link to a Comp Cam from Summit that would probably be ideal for your goals. http://www.summitracing.com/parts/cc...make/chevrolet You might want to call Comp's tech line and ask them what valve springs they recommend for it. While you can more than likely get away with your stock springs, provided they're not too wore out, a new set of matching springs would be even better. That cam should give your 305 a good shot in the arm without being too radical, and since you have a MAF TPI system, your computer would probably handle it pretty good.

 

Thanks to everyone for the very informative reply's and links.

 

All you need is a cam one step bigger than the stock cam. You're not doing any head work so keep it simple. Keep the stock gears.