# To change the cam or not



## spaceball 1 (Feb 27, 2009)

I need advice from someone who knows cams and pontiac motors better than I can figure out . This is what I have now a 1971 lemans with a 400 ci forged pistons, 94 heads, and the cam is a Elgin E1083p cam lift int .310 exh .325 lobe centers int 107 exh 117 advanced duration 290 int 300 exh .050 dur 224 int 234 exh. I have 2 intakes a edelbrock performer and a old torker the carb will be a holley 750 until i can work on a quadrejet for the car. The trans is a th400 with a breakaway torque converter and 2.76 gears in the rear end the car was never set up good or fun to drive. My goal is for a good street car that can cruse longer distances and not spend too much more money now as I am tiring to put the car back together this year. 

Thanks in advance Tyler


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## spaceball 1 (Feb 27, 2009)

Maybe I should rephrase my question, the torque converter is new and was looking for advice on any other mods like a cam to get the fun back into the car. I am also putting A/C back in and will change the rear end later when I have the money, but I am looking a motor work now since the motor is on a stand and will be going back in soon.

Thanks


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## BearGFR (Aug 25, 2008)

spaceball 1 said:


> Maybe I should rephrase my question, the torque converter is new and was looking for advice on any other mods like a cam to get the fun back into the car. I am also putting A/C back in and will change the rear end later when I have the money, but I am looking a motor work now since the motor is on a stand and will be going back in soon.
> 
> Thanks


Hey Tyler -- it's a hard question to answer. You've got to think about the car as a system - "everything" depends on, is connected to, and influences "everything else" - and "everything" has to work with and live within the constraints - both the ones you choose (like how and where do you want to use the car and what's important to you) and the ones that are forced on you (like fuel quality).

Whenever you change a factory flat-tappet cam for something else, there are going to be additional costs over and above the cost of just the new cam alone. The cam, lifters, pushrods, and rocker arms all establish a wear pattern such that over time the parts have become 'mated' to each other. Changing the cam without also changing all these other components is just asking for trouble. And if you're going to change "all that" you might as well keep going and replace the factory rocker studs and nuts with larger, fully adjustable pieces.

First things first though. With that rear gear and torque converter you're running you can't go very extreme on the cam without making the car a real dog. That's because the way a "big" cam "works" is it shifts the motor's peak volumetric efficiency (where it makes peak torque) higher in the rpm range --- at the expense of making it less efficient/producing less torque at lower rpm. So, you need to think about how you want to be able to drive the car, decide if you want it to be a highway speed cruiser or an all out stoplight to stoplight bruiser, or somewhere in between. You should also think about your budget. If you want the fun of a "rumpity rump" cam then you're going to have to change the gearing and converter to keep it from being an embarrassment anywhere except sitting still and idling in the parking lot.

Few things suck as much as getting a project "almost done" and then having to stop because you ran out of cash, so be honest with yourself and don't try to cut corners. It'll just bite you.

Bear


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## spaceball 1 (Feb 27, 2009)

I know that this is a complicated question and should have said earlier that the motor was rebuilt 5000 miles ago with the cam, 1.6 roller rockers, ARP studs, and all that it needed at the time. The car was going to have 3.73 gear in a 12 bolt and I have a high stall converter that was in it but never got the rear end done and now I want to cruse more than drag race. The old setup sucked bad with that gear and i realize now the current motor setup is not perfect for what I have or want to do with the car. I am just curious if any motor work now is worth it or not to get it closer to goal. The rear end can be done later I just have to get my garage back and make this car a roller this summer.

Thanks
Tyler


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