I am about to get an 85 vette motor, but the guy needs his cam. What cam should i get that can still be used with the cross-fire intake. I am going to get the vette chip for the cross-fire. Thanks for the help.

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82 cross-fire, 410 gears
700r4

 

GJ,

The guy is doing you a big favor. That cam is pretty good as a door stop, but lacks a lot when opening valves.

And I am probably mistaken again, but weren't the '85 Corvette engines TPI instead of CFI?

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Later,
Vader
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"Get UP - Drop the bombshell!"
Adobe Acrobat Reader

 

Vader, the car is TPI but i am going to use my old intake from the 305.

 

Good luck. I helped a couple of guys out with X-fire stuff a while back and they both aborted and went with carbs about 1/2 way through the project becuase it was cheap and easy.

Here's the usual stumbling block: The x-fire is basically a speed-density FI system. It has no MAF sensor to directly read how much air is going into the engine. So massive changes to an engine's basic breathing characteristics are not taken kindly by the ECM. Adding 50 odd cubic inches down below qualifies as "massive changes to the engine's breathing characteristics."

SOOOOoooooo..............

You need the ECM to be reporgrammed to compensate for this (I don't know of anyone who burns x-fire proms and that's where most people bailed out of this kind of project) or...... If it's a very mild 350 you can get away with just installing bigger injectors (don't know where you'd buy x-fire TB injectors) or an easier way of effectively accomplishing the same thing- bump up fuel pressure about 5 PSI to make the stock injectors act about 15% bigger than they actually are (which may be more than your stock in-tank electric pump can handle since it's a low pressure pump)

If the 350 you are building is much hotter than stock then just bumping up fuel pressure or increasing injector size will not be enough. You will need a custom chip which, as I said above, I don't know where to get.

You see why everyone just goes to a carb setup in the end? This project is a PITA and should only be undertaken as a labor of love and not a serious performance avenue.

BTW- 'Vette x-fire engines use larger bore throttle bodies that will bolt to your 305 mainfold just fine and they also come with larger injectors to match.

THat's not an answer to your question exactly but it should get you thinking of the real challenges involved in this setup. Stabbing in a cam is easy, making it work with the rest of the setup is difficult.

 

Almost any cam in the 210-216 .050" duration range would be computer friendly, subject to the extreme limitations of that throttle-body system. There is some degree of hope though. These guys have at least some of the most-needed stuff for it.

http://www.turbocity.com/CorvetteCro...ECMUpgrade.htm

Honestly though, if you're interested in any degree of performance at all, you might want to seriously consider getting rid of that Cross-fire. They were laughable enough as far as speed when they were new (I know, I well remember how my 83 HO Z28 would absolutely toast the F-body 305 ones as well as the 350 Vette ones) and they haven't gotten any more attractive with age. I honestly believe you could take an original LU5 long block and put a stock L03 setup on top and get 15 or 20 more HP with that, bad as it is, than the Cross-fire would do. That system is about as anti-performance as it could get: to put it in perspective, think of it as being a Cavalier motor, except 2 of them stuck together. Look at the intake runners where they connect to the head, and see if you don't find something wrong with that picture.

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"So many Mustangs, so little time..."
ICON Motorsports

[This message has been edited by RB83L69 (edited August 30, 2001).]

 

Thanks RB83L69 and Damon. The intake does have it restricions, like the intake runners curve up so that is a restriction. The reason I'm running the cross-fire is i can pass emissions, and because it is factory.
Thanks for the very useful advice about the type of cam I can use.

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82 cross-fire, 410 gears
700r4

[This message has been edited by Gerald Jackson (edited August 30, 2001).]