im building a 350 TPI motor and am in the middle of choosing a cam. right now, im trying to decide between the zz9, LT4, and the comp cams 268XE. how do i know if they will work without burning a custom chip?

 

This is an entirely subjective question. They will all 'work' without a custom chip. None will be close to optimal, but with the smallest duration numbers of your choices (IIRC) the ZZ9 would probably 'work' the best.

 

ok, i will re-phrase it. how can i tell if a cam will work well with the stock computer? i just dont want to have the motor in the car running terrible b/c i wont be able to get a custom chip until after the cars been on the road a while and i would like it to be driveable in that period of time. thanx

 

the CRANE #114132 runs great with the stock TPI system, the CRANE #114142 is at the ragged edge of what will not cause problems or cause codes to display, all the cams you mentioned will not run correctly with the stock chip! IVE run 13.4@ 101mph with the #114132 cam in my vette so dont think its super mild

http://dab7.cranecams.com/SpecCard/D...1=Display+Card

the #114142 got me to 13.1@102 but overall it was not as well matched to the TPI systems torque curve and rpm requirements

http://dab7.cranecams.com/SpecCard/D...1=Display+Card

 

How do you know how well it will work with the stock chip? Easy. The stock chip is pretty close on a completely stock engine. So the closer you are to a completely stock combo, the closer the chip is. Thats why in my previous response i picked the ZZ9, because it is the smallest of the grinds you listed.

I know this doesn't help you much, but a better answer cannot be given. Their are no hard and fast rules for how much cam you can run with a stock chip. And depending on luck and skill, people have had different levels of success running different cams without burning chips. Your best bet though is to stay on the small side. Without knowing more details of the combo you're building and your goals for it, it's impossible to help any further.

 

The first cam grump mentions is a good example of a mild grind that isn't too far over stock as to cause any real driveability type issues with only 210/216 @ 0.050.

The second (216/226) is on par with the comp 268XR and LT4 hot and is too much to run with a stock computer unless you just want a lumpy idle and no performance to match. You'll also need decent heads and a good amount of intake work to make that one work right.

 

Ed Maher
is correct here, the only reason the #114142 works better (but not much) that the other cams YOU mentioned is its got a wider LSA that better matches the EFI/TPI systems requirements, (it still idles like crap and is only happy over 2000rpm, it does pull slightly harder in the 4000rpm-5000rpm range but in all other rpm ranges the #114132 cam has it beat! the #114132 runs great with only a slightly lopey idle and good power over most of the engines rpm range, both pass emissions but at least from my experiances with several dozen cars and TPI cam swaps thats about the best non-roller cam available for all around driveablity plus a power boost with zero problems (#114132)

 

If you want my opinion....

Don't base your cam selection on "which cam will work best w/ the stock computer until I can get my chip changed". If you do that, you're cheating yourself and your car. Pick which cam you WANT, and which cam you think will work best w/ ur combo, and if you have to get a chip burned for it to run like you'd like it, then so be it...wait till you can get enough $$$ for both. No compromises....do it right the first time.