Does anyone know the best head swap for a lu5 crossfire? Also could i gain anything from switching to carb? I have plenty of used carbs and intakes to choose from, so the cost of buying parts will be minimal. I also have a few sets of heads off of some 350 trucks. Not sure of the casting numbers, just know they are stock. Are the combustion chambers in 350 heads bigger than on a 305 head? And wouldn't you loose compression if they were? any information would help greatly.

 

The LU5 has decent heads for a 305, the 416 heads would be good to port yourself. Check Sitting Bulls sig and I think F- Bird88's sig for good porting info. Stay away from 350 heads, the big chambers will kill your compression ratio. The exhaust on those is horrible restrictive if still stock, and the actual cross fire intake manifold was not a good design. Switching to a carb could make a big differance if you adress the exhaust problems too.

 

Well im glad that the heads are good. So all i really need is an intake and carb. I already have a set of headers, and some pipes without cats.
One more thing that im wondering about. I had just put a new tank and fuel pump in. If i switch to carb could i still use the electric fuel pump? Or would i have to pull the tank one more time to replace the fuel pickup?

 

You should be able to use your electric pump, just run a good quality regulator on it.

 

You will need a non-CCD also.

 

what is a non ccd?

 

Computer
Controlled
Distributor

Why not just slap on the headers you have, port the intake, and got run some mid 14's?

 

Thanks Tom. Thats probably the best advice that ive gotten so far. I change my mind just about every other week. Last week was carb and this week its keeping the xfire. Im working on this car with only the help of the people on this message board. I figured that being my first project that I would start with a carb. I read so much negative stuff about crossfire injection. Ahhhh. all I really want is a kick @ss Camaro. I dont care that much about having a 500 hp monster. Might as well keep what ive got. Just need to get rid of that exhaust leak. It sounds horrable.

 

Glad I can help. Most people that give negative information about CFI don't know what they're talking about. They heard from their uncles, friend, blah, blah, blah. Almost everyone I've ever seen post on this board criticizing CFI, DOESN'T HAVE IT! and those that do have it, will tell you fairly straight up, what the "real deal" is.

So here is the deal;
The CFI system is no doubt, restrictive. In totally stock from, the CFI intake can support up to about 240 hp. Good enough to get you into the 14's.

A ported intake will support up to about 310 hp. Good for low 13's. Keep in mind this is what the induction system will support. Other changes have to occure to the rest of the engine, but those changes are the same as on any other engine (i.e. headers, exhaust, cam, etc).

So the bad thing about CFI is how restrictive it is in stock form. The GOOD thing, it that for almost NO money (just time spent porting), you can realize HUGE gains. In other words, you can pretty much bank on being able to build up to 300hp w/o having to spend any money on the induction system. Above that, you'll have to look at an alternative such as the X-Ram, the Offenhauser Cross-Ram, or the Edelbrock SY-1, etc. Those will support pretty much anything you can put under them.