Hi all,
I'm getting ready to rebuild the 305 in my 81 Z28. It's bone stock with 150K miles and also has a factory 4 speed. I'm looking for recommendations on upgrading the cam but still remaining CA Smog legal. I do not plan on any other upgrades. Intake and Exhaust will remain factory stock. Thanks for all your input!
John

Are you looking to make it TECHNICALLY emissions legal or just to pass the tailpipe sniffer and an external visual? Technically emissions legal I'd go for the Edelbrock Performer cam (and matching aluminum Edelbrock Performer EGR intake, if you have a few extra bucks to spend).

If you just want to pass the sniffer and a quick external check I'd buy the Summit K-1102 cam (it's the exact same cam as the Edelbrock Performer but cheaper and doesn't carry an emissions certification), again I'd still do the Edlebrock Performer EGR intake for both power and emissions compliance PLUS I'd replace the stock dished pistons in your 305 with a set of flattops to raise compression- it can make a nice bump in torque and power across the RPM range and since you're rebuilding anyway it doesn't cost any more to buy flattops than it does to buy another set of dished pistons.

x77 D80,

The biggest problem is that the stock 80 305 will be limited unless you get into the engine internals and take care of the intake and exhaust systems. Just installing the cam without doing some intake and exhaust work would help only little bit but it will limit the performance of the cam.

Damon is correct about a good intake like the Performer EGR or a Weiand 8000 EGR. Either dual plane will help the engine breathe better and all the cam to get more air in.

There are a couple of California legal cams by Comp and Crane that have E.O. numbers and will work as well as the Edelbrock or Summit cams Damon specified.

I would seriously suggest you get the exhaust system redone with a good high-flow cat and a three in pipe to a nice cross flow muffler in the stock location to keep things legal.

One other thing to note, unless your car was an original California vehicle with the electronic carb and the ECM unit, you could swap in a mild 350 and pass the sniffer test.

There are a few people in your area that are available to help you with some of the performance upgrade suggestions. Feel free to PM if you have any questions.

Good Luck!

+1
good advice above
A modern OBD 1 cat will make a world of difference on that car. 305's are inherrently underpowered motors, I think the most powerful one ever built was rated at ~205HP (87 IROC Camaro) A standard GM targetmaster replacement 350 which will pass any emissions test and can be had for less than $2000 complete makes ~250HP.

Until they run the block's VIN code and find out it is a 350 and then you are in............

pdq67

you could build a 331 stroker motor if you had the $$.

Per CARB standards you are allowed to run any engine in the "family" meaning that a car with a 305 could run a 283,302,327,350,or 400 without any legal issues as long as it retains all of the smog equipment and will pass tailpipe.

I have a Comp Cams 265DEH in my 350 and is smog legal. It's a dual pattern and the idle isn't too bad either.

Right!

As long as the CORRECT smog stuff for both the car and the engine is on both!!

And I forget, but I think it is car over engine, BUT I may be off here??

In other words, you can't drop a '58 392 Hemi into a Magnum S/W!!

pdq67

The offical rules are complicated on emissions. Some it's a same or later year motor is OK to swap in, sometimes it's gotta be an option that was at least available in that year, sometimes the tranny type has to match, sometimes not.

An emissions-legal 350 replacement motor would probably be technically legal but would it be legal with a 4-speed behind it (which was never offered with the 350 that year)??? Don't know. You'd have to ask around locally to see what's OK for sure and what's not. Usually if it looks good from the outside and passes the sniffer they let it slide- even the People's Republic of Kalifornia doesn't go so far as to rip your motor apart to check internal pieces.

81s have computers, you need a Crane compu-cam to be legal. 204/214@0.50 duration, .423/.446 lift.
Dont know if its carb legal, but gms zz intake has egr and is more of a true performance intake.
hipo cat would be good too.

The GM ZZ intake with EGR is cast by Edelbrock and is similar to the EGR Performer.

I think Crane has an EO number for that cam if not mistaken so it would be fine, imho!!

It's basically a Performer cam so is fine, again, imho!!

Please check Cranes site to be sure tho...................

pdq67

I want to thanks everyone for their input so far. But for this car, all mods have to be hidden. Not because I'm afraid of passing smog, but because I want the car to "look" factory correct. The car is all original with tons of paperwork including a build sheet, window sticker, etc so the 305 will stay in the car. I pulled the motor and so far found a flat lobe and several very worn lobes. I'm amazed the car ran as good as it did. My plan is to model it somewhat after the 83/84 5.0 HO motor which was carburated and was advertised with 190 HP (wow hang on!). I will be upgrading the cam with a summit K1102 Advertised Duration 262/ 272, Lift .420/ .442 that Damon suggested above. It's very similar to the EO certified Crane cam. I'll also be ditching the stock 1.84 intake valves and replacing them with 1.94's and having a friend of mine clean up the bowls in the heads with his serdi machine (just to be choked up with exh manifolds) but that's the way I want it. I'm looking forward to what it can do. I know it will be fun at least with the 4 speed and 3.42 rear.... Oh, and I'm also keeping the original stock dual resonators but will be replacing the flat pancake cat with a high flow unit... Stay tuned.... I'll have some pics up soon.

John,

Knowing the quality of workmanship you put into your pace car and other projects, I know you'll be doing a good job on this. I know how you feel about "Originality" and think it is great for nearly all 1st gens and many early 2nd gens but IMHO, the collectibility of an 81 305 4-speed will be many years before it starts to gain interest. Probably by the time your kids start driving, it will become a semi-classic but hopefully still fun to drive!

Since you're pulling the heads anyway, why not pull the exhaust manifolds and have them ported by Extrude Hone or Brzenzki? Build up the short block as a stroked 305 or mild 350 with a little more cam for torque. Get a GM factory Aluminum EGR intake and port it. More than anything else, swap out the stock gears for something a little more peppy like some 3.42's with a limited slip as the stock gears are probably only 2.73's.

This is your car and I know you'll do a good job on it but why not have a little more fun with it and build a stock appearing "sleeper" that's really fun to drive?