i am replacing the stock heads and manifold with a pair of vortec heads and a vortec manifold and i am going to be also doing a cam change at the same time what would be a good roller cam to complement the new heads and manifold


i want one with a lopey idle

was looking at a comp cam or a gm performance parts cam


3in flowmaster american thunder exhaust

 

Moving to 3rd gen Tech...

Thanks.

 

GM - LT4 HOT

COMP - XE274HR

Every one is going to tell you they are too big, but that is because they have been diluted into believing this by to many people saying the computer won't except it. Well it will, and I have drove the cars with them in TPI and TBI set ups.

Martin

 

Remember that if you go with anything over ~.470 lift with the vortec heads that you'll need to have work done to them to have them accept the higher lift cams. The stock springs suck ***. My recommendations would be a LT1 cam if you dont have any money like I did, or a ZZ4 cam if you can work with the computer a little. Id rather have the ZZ4 over the LT1.

 

in the process of removing my 305(carb) and going to 95 impSS LT1 w/hotcam kit and 10.5:1 cc. w/30 over should be a great time.

 

A lopey idle is not the sign of a hot car. It just means that the engine has a hard time running at low rpms and can't make power until it is in the +3500 rpm range.

Sorry

 

I agree that you should use the lt4 hot cam I have it in my car and it is amazing. It also has the lopey idle that you want. You will have to get 24lb injectors and a custom prom. The car will run with the stock chip but it will set some codes. I'm still running the stock chip my chip just came in. SO now I will be able to start tuning

 

Chikn, are you running 1.6 rockers?

 

will the lt4 hot cam work in a 305 TBI

before i put on the cast vortec heads i replaced the stock springs with a comp cams set that is good up to .575 lift

should i keep my 1.5 rollers or upgrade to 1.6

i think the lt4 hot cam gets .525 lift with a 1.6 rocker is that to much for a 305 and will it effect the stock ECM

 

IMHO .525 lift is a bit much on a TBI engine, no matter what heads you have. Since you have roller 1.5s already I would just stick with them. That still gets you almost .500" lift, but will help keep the vacuum and port velocity up.

 

so with a tbi setup can i still run the lt4 hot cam or will i run into problems with vacuum


would it also be better to upgrade to 1.6 rockers

with that much lift you are sure that it wont effect the stock computer

what about getting a new chip burned?

 

The LT4 HOT cam doesnt even work with the stock TPI, so it'll never work with a TBI engine.

I would recommend the Compucam 2030 for a 305 TBI engine.

 

Just because some guys have hotcams in their 305 and think it's the best thing since sliced bread doesn't mean it's the best thing for you. I'd really like to see what other mods these guys have, and most importantly, what their 1/4 mile & dyno numbers are. A hotcam is WAY too much cam for a mild 305, and definately more than a stock TBI setup is going to function around.

First of all, are you running L31 vortec heads or the 305 equivalent? The L31s flow very well, but on a 305 you're going to have a lot of valve shrouding because of the cylinder bore being so close to the valve. I wonder if a high lift cam would help offset that problem, or if its effects would just be masked by the shrouding issue.