305 crossfire injectors on a 84' vette?

[unknown84vette]

Are the 305 injectors able to work on a 84' crossfire vette with a 355ci engine? I ask because I'm curious if someone has discovered that running the smaller injectors at a higher pressure works better for fuel delivery. I have heard that the stock 350 crossfire is prone to running rich. Can using the smaller injectors from a 305 lean things out?

 

[xfirez51]

Are the 305 injectors able to work on a 84' crossfire vette with a 355ci engine? I ask because I'm curious if someone has discovered that running the smaller injectors at a higher pressure works better for fuel delivery. I have heard that the stock 350 crossfire is prone to running rich. Can using the smaller injectors from a 305 lean things out?

Are these the Corvette 305 found on the Calif. cars? Xfire injectors are staggered 62/65 psi to make up for loss if pressure between front and rear tbi's. You should also change calibration.

 

[unknown84vette]

xfirez51,

I am thinking about the injectors used in 305 crossfire Camaros and Trans-ams. There was the 1980 305 California vette which I think used a carb. That car made Time's 50 worst cars of all time list, which is completely wrong, considering its missing the 1987 Nissan Sentra and instead lists a vette. I used to have that Nissan.

 

[KANE]

xfirez51,

I am thinking about the injectors used in 305 crossfire Camaros and Trans-ams.

I've seen folks with Tuned Port Injection (TPI) run 305 injectors on 350s... and yes, they have to crank up the fuel pressure to do it. But I've never seen folks do it with TBI or crossfire.

I don't see that as a viable long term solution. Realistically, injectors need to be sized according to the motor. Also- the bores of the throttlebody should be sized to pass through the appropriate CFM.

 

[unknown84vette]

Kane,

Crossfire throttle bases for Camaro, Trans-am, and Corvette are interchangeable, each having 46 mm bores. 1/2 of the crossfire TBI setup can run a 4 cyl engine, but I don't know what if any GM car that was tried in.

Injector towers can also interchange. It makes sense that injectors have to be right sized. If I did run a higher pressure, I would make sure to replace my fuel pump. 84' Corvette injectors are what I have on hand, but I'm always looking to see if something can be made to work better. My line of thought is that a smaller injector and higher pressure would spray out the fuel faster. I'm not sure if faster is better, though

 

[KANE]

Crossfire throttle bases for Camaro, Trans-am, and Corvette are interchangeable, each having 46 mm bores. 1/2 of the crossfire TBI setup can run a 4 cyl engine, but I don't know what if any GM car that was tried in.

FWIW- I think some of the iron dukes or 90s Cavaliers may have had a 1 barrel TBI set up.



Shifting gears...

What is your cam size though? You have a 355- correct? What do you think you are pushing, power wise?

I was just wondering are your getting enough air through those bores to feed that mill. That is a side issue to your question though. Sorry for the hijack!

 

[unknown84vette]

I'm glad the cam question came up. That is one thing I've been thinking about.

I don't know what camshaft I have. It was rookie mistake. I bought the vette this last October. I paid $1700 for the 84' with new paint, tires, auto trans, alternator, but a bad engine. When the engine went, the last owner gave up on it. I had very little mechanic's experience at the time. I got the engine rebuilt in December. That machine shop is not the same one where my throttle body bases are. These guys were good. I didn't know anything about cams at the time, other than to ask on its condition. The engine builder said the cam looked great, but recommended new lifters, which I got. The engine was partially rebuilt by a previous owner; grinding the crank 10 under, but leaving the stock pistons in place.

I installed the engine, and all that is left is the crossfire throttle bodies and some wiring. Now that I know that cams can differ, is it worth taking things back apart to install a known cam? Is it possible to find out the cam profile by removing a rocker cover and measure the pushrod movement while turning the crank?

I'm not sure what kind of power I'll get, but I'm trying to squeeze out a little more HP and MPG than the stock crossfire. Its a good engine, but at the same time I understand its not a modern LS engine. So far I have bumped CR to 9.33 by 0 decking the block and using # 487 cast heads. The new rotating assembly is lighter than stock. A K&N air filter only cost twice what a paper filter cost. I have some ramhorns roughed in, but I plan to go to a true dual exhaust with long tube headers. The rebuilt engine is bored 030 over, making it a 355.

 

[DRIVEJUNK]

Tbi

FWIW- I think some of the iron dukes or 90s Cavaliers may have had a 1 barrel TBI set up.



Shifting gears...

What is your cam size though? You have a 355- correct? What do you think you are pushing, power wise?

I was just wondering are your getting enough air through those bores to feed that mill. That is a side issue to your question though. Sorry for the hijack!

82 Camaro 4 cyl TBI

 

[terry82]

i would put in the correct injectors because they will be undersize for the 350.the over rich problem was corrected with a new prom.you dont know if the cam will work yet ,so dont change it .try it first with what have then start making changes.the stock cross-fire will get you over 20 mpg ,if all is running right.