This should be an easy question, I hope. Witch do you guys think will yield a greater power gain, hp and tq? Mildly ported stock heads with 1.6 rocker arms and stock cam, or a LT1 cam with rebuilt stock heads and 1.5 rockers. I'm more into AutoX than dragracing if that makes a difference. This is a relativly stock motor, and I can put a ported stock intake manifold on either of these senarios if you guys think it will make a difference. What do you guys think? Thanks in advance.

 

In my opinion neither option is incredibly wonderful. The stock heads stink. The stock camshaft stinks. With some porting the stock heads can be made to be not quite as stinky, but they'll still smell bad. The stock camshaft stinks and the 1.6 rocker arms would probably not help a whole lot. Given the choices I would mix and match a little bit: Mildly ported heads, stock rockers, and LT1 camshaft. I don't know if that exceeds your budget or not, but it should give better results than either of the two that you put forth in your post...

 

I'd go with the ported heads and 1.6 lifters if you needed me to choose between your selection. The stock cam has a small lift and the heads actually do okay if ported well.
What I would do is port the heads and install Lt1 with 1.5 stock rockers. Lt1 doesn't need more lift and is perfect for the 305.
If you can wait a bit longer before doing the heads I would do the cam swap and then later on try and find some L98 vette heads (58cc). This way the heads will work on a 350 if you ever decide to ditch the 305.

 

Hello Sharp.. Where do you auto-x at now? Still at the speedway or back to parking lots down at the stadium?

Do you have to pass a sniffer test over there in Cobb county?

If I had to do it over and was starting without any parts on hand;

1. Exhaust: Headers and y-pipe, high flow cat if inspected, and cat back of your choice. Just make sure everything if not for the LO3 but for say the L98 eng. You want 2.5" pipes to the y and 3" from there back with a 3" cat if necessary.

2. The cam can be any of the LT series with some opinions on which one is best. (LT1 of different years or LT4) I'd say get the cheapest available.

3. Intake: dump the stocker and get the cheapest with egr if needed and make or buy an adapter for your TBI.

4. Port the stock heads only if you don't have the cash to get a set of TPI stock heads for cheap and port them. (081's were on TPI cars of the same year and will have egr ports if needed and will fit the cheapest intakes) These will be your biggest bang for the buck.. Go to Road Atlanta sometimes when the American Sedans are running and check out the power they get from these heads. They are required by the rules to run 081's or 416's (stock 305 heads of different years)

5. Do the ultimate TBI mods to your throttle body itself and the adjustable pressure regulator mod.

6. Make sure that you are not using the stock breather set-up

Sorry to be so long winded, I tried to keep to the questions asked but I felt that without the exhaust and breather mods you would still have bottlenecks in the package.

Later

 

another option is to pick up 87-92 305 tpi heads , maybe 50-100 dollers, have them ported and use them instead of tbi heads . tpi heads flow alot better them the tpi heads and they use the same bolt pattern asd the tbi heads.

 

Ohh, I didn't put my 3 inch in and out cat with 3 inch I pipe and a flowmaster crossflow with dual 2.5 outs in my sig. Woops. And I don't have an open element but I do have the cowl setup from an 84 ta, about equal I think. I do have another tbi with the top ridges removed whitch will also go on. The reason I ask about the heads is because I happen to have a set of rebuilt stock heads sitting in my garage. This is more of a time issue than anything else, I will only have maybe a weekend to do the work myself and I have never gone that far into an engine before. I know that I can do it, but I want to go slow to make sure that I don't make any mistakes. I'm trying to have it ready to race with carguys in NC the feb 14 and 15.
Sup DM91RS? Yea I have to pass the sniffer in cobb, and this is my DD, so I don't want to compromise that too much if I can help it.
What about the port matched manifold? Will this lower vilocity too much? Thanks for all the responses, and I must say that I'm proud of all of you, not one mention of changing to a 350. Thanks.