I am building a 383 LT1 I have been told that a carb would make more power, and with a mechanical secondary that I can close off while driving on the street I could keep the fuel mileage close to the same with EFI. What carb intake will fit my lt1 heads? I was told that any manifolf for vortec heads would work is this true? I also asked this in the nitous section but couldn't get the answer I was looking for I am also putting a wet kit on this car what is the best way to put the T in my fuel line?

 

GM Performance 24502592 - GM Performance Carbureted LT1 Intake Manifolds - Overview - SummitRacing.com

these are the only intakes I could find. Apparently the LT1 heads are unique/ different from vortec heads. Im not sure about the nitrous but I know that summit and jegs has a lot of complete kits available online or in their catalogs.

 

You are not going to setup a carb that is going to get as good as gas mileage as EFI and as fast. The only time Carbs wins out over EFI is when the motor is built so radical that the EFI system can not handle the uneven vacuum. Many dragsters still use carbs for this reason. Carbs work great as one trick ponnies. EFI will always win when you want a car to do many things (like drive thru town and go fast down the quarter). The old close the secondary off trick has been around since the 70's. I never remember and of my old cars getting above 13 MPG. Heck with vacuum secondaries they will not open until you stomp it. Those car did not do well either.

Have you put any thought into your ignition system? Cause if you are dropping the EFI your going to need a complete new system. You know you will have to cut your cowl to fit the carb? Your also going to need another hood.

LT1 and other SBC heads are not interchangable. You can not use LT1 heads on other V8s due to the reverse flow coolant. I assume that means the same for the intakes. You will need a LT1 intake.

Do not T into exhisting fuel line unless you have upgraded that system to handle the max HP you plan on making. It is better to have a stand alone fuel pump for your wet system. If your wet system runs low on fuel pressure at high RPM because the regular injectors are using up fuel you will fry your motor.

 

I plan to upgrade the fuel pump and ignition prob MSD 6AL and coil. I want to keep my EFI it will keep my stock look other than the bigger throttle body and NOs nozzle, but I know it is going to cost thanks for the help.

 

please listen to Gorn unless of course the vehicle is 90% track use and 10% driving to a car show a few miles down the street. I read posts about "old school" etc but why not compare a 454 chevy from 1970 to the lil ole 5.0 in the 2011 Stang. Or, a small block from the 60's or 70's to a V6 in the Honda minivan of today. A new v6 Camry will outrun many older "muscle cars"


One question, why did you already decide on NOS vs any of the other nitrous vendors?

 

THe MSD 6A and 6AL do not replace your ignition system they enhance it. It enables you to do things like multiple spark, rev limiter and allows the use of high voltage coils for a stronger spark. You must still maintain the trigger mech for your stock dizzy to make these boxes work and that means maintaining the EFI.

Like Gorn said EFI gives you the best of both worlds, economy and performance. Why do you think that we have cars today that can build over 500 HP and still get close to 30 MPG. Do that with a carb... you cant. With a carb you can get good mileage or good power but not both at the same time.

The best setup I have ever owned for power and mileage was a 327 with Tripower, and progressive linkage. This enabled me to use a 2bbl for up to 1/2 throttle but by the time I was WOT I had 6bbl feeding my engine. I got clost to 20 mpg if I keept my foot out of it but I could watch the needle move when I would play. This engine was stuffed into a 1960 Chevy Shorty stepside with a 400 trans.

Most people that do not understand EFI will tell you that you can do better with a carb. They are wrong. Again if carbs were so much better why are there no new cars today being built with a carb? EFI works on the same principals as a carb, but it is accomplished with different methods.



Massey