the zz4 cam does it fit in 305 tpi lb9??? If you say yes, what are the modifications i am suppose to do (head, intake, spring, exhaust,...) My car is stock.




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trans-am 91 3.08 posi 5.0 lb9 5 speed stock

 

Yes, a ZZ4 cam will physically fit into the LB9 305, but will likely be a little too much for the small displacemnt.

If you decide to install it, you will need different valve springs and the necessary machining to accomodate them, screwed rocker studs, probably longer push rods for the smaller base circle, a custom PROM to compensate for the lower vacuum and rougher idle.

You will not be able to take full advantage unless you provide for greater intake and exhaust flow. If you have an automatic trans, you might want to consider a higher stall speed torque converter to compliment the cam profile.

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Later,
Vader
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"No matter how hard you try you can't stop us now..."
Adobe Acrobat Reader 4.0

 

So, which cam will be the best for me without any modification???? With this new cam, how much hp will i gain???

My car specs are in my signature.

thanks

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trans-am 91 3.08 posi 5.0 lb9 5 speed stock

 

up


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trans-am 91 3.08 posi 5.0 lb9 5 speed stock

 

Stall,

By "without any modification" what exactly do you mean? Do you plan to keep the stock springs and retainers, push rods, and pressed studs?

If that's the case, I wouldn't advise going much beyond 0.450" lifts unless you want stressed and broken springs, bound coils and bent pushrods, or worse, a new cam that is destroyed. The stock springs aren't much good past those lifts, and the pressed rocker studs won't survive the strain of higher lifts at higher RPMs.

Additionally, the TPI won't tolerate a lot of overlap without reprogramming the ECM/PROM. On the positive side, the smaller valves of the 305 and restrictive passages in the heads will limit the effects of overlap, and its longer bore/stroke ratio is also a bit more tolerant.

With stock valve sizes, I'd try to keep the duration to a maximum of 220° and lifts under 0.450" with stock springs. If you were changing springs, 0.490" lifts might be a better limit.

I'd still be a little concerned about the rocker studs at anything over 0.450" lifts, but you might get by - maybe. Screwed studs are cheap and pretty easy to install.

The net increase is a crap-shoot. You will almost definitely lose some torque on the lower end, but gain a flatter torque curve on the high end and the resultant increase in horsepower. I'd hate to predict a number, but I know you would feel a difference and probably measure it on your time slips.

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Later,
Vader
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"No matter how hard you try you can't stop us now..."
Adobe Acrobat Reader 4.0

 

thanks a lot vader !!!

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trans-am 91 3.08 posi 5.0 lb9 5 speed stock

[This message has been edited by stallone (edited February 11, 2001).]