when converting to efi which intake is better(mileage and power)
for a 390hp (using carb) 350 camaro

an LT1 or stock TPI?
how about these compared to a single plane (or dual plane)with 4 bbl throttle body and drilling intake for injectors

 

Each setup has its' own pros and cons. TPI has tons of torque at a low RPM but tapers off quickly at high RPMs. The LT1 intake has a much more flat torque curve so what it lacks in torque at low RPMs it makes up for at higher RPMs. What do you plan on doing with the car? If it is mainly for stop light "racing" TPI is a better choice, for highway grunt go with the LT1. Gas milage is great on either system, it just depends on your cam/heads/driving style. Give us more detail on what you plan to do with the car.

It is possible to convert a carb manifold to EFI. You will need to make or find a 90 deg bend with a throttle body adaptor on it. This setup will require and aftermarket EFI system or you will have to burn your own proms.

 

It sounds like you already have a 390ish hp carbed engine, and are wanting to swap to a EFI setup to me, that right? If so the stock TPI intake will suck a ****load of your power out. I would definitely say go with a LT1 intake over TPI.

However, assuming you have no EFI stuff at all and need a whole swap solution, here's what I'd do. I think the cheapest/easiest route is probably going to be to buy a complete TPI setup with the whole harness and computer, all sensors etc for around $550ish. I think a couple of the vendors with ads at the top of this page selling used stuff offer setups like this. You can also find similar deals in the classifieds. Sell the TPI intake itself for a few bucks, while keeping everything else and buy a holley stealthram intake to replace the TPI for $450ish. Bingo, plenty of ability to make the power and it won't cost a fortune. The stealthram works with the throttle body, the injectors, sensors, etc from the whole TPI setup.

A LT1 setup would be comparable, but I would think you'd spend more to get a complete LT1 setup with all sensors, wiring harness, ECM, etc. Maybe I'm wrong....

With converting a carb intake setup to a throttle body type EFI, you'd still need the wiring harness, all sensors, ECM, etc. Plenty of aftermarket ones are available but they're pricey. I really think your best/most affordable bet is to get the complete TPI setup with everything since it's cheap, then replace the TPI itself with the stealthram intake. Good setup...

 

im using vortec heads,
i know about the port and mounting bolt mismatch,i do have an lt1 intake ,i thought about welding up the runners porting to match and redrilling the heads,as with the other mods that have to be done

will the rails and harness off a stock tpi fit the lt1?

i like the holley commander 950 ecu (what do u think)
also how about using ls1 injectors?

i see Ray87 has vortec heads(what do u have for induction?)

thanks alot for helping me with info

 

how does a 2 plane manifold work?(ie. performer rpm)
using a holley carb for a throttle body
it shouldnt be too difficult to adapt a tps and a iac motor to it

does the lack of plenum kill it?

 

(1)the LT1 is a reverse coolent flow engine that reqires a totally differant block and heads, water pump,ignition system to match the intake or a total reweld/mods to the lt1 intake to work on the standard 23 deg heads

(2)the tpi intake will need serious&expensive mods to support 390 plus hp and a ECU to control the EFI

(3)your best route is to have an EDELBROCK super victor intake modifyied for injector bungs and fuel rails and add a holley 1000cfm 4-barrel throttle body, if your useing a G.M. ECU to control the EFI (about 450hp max without serious mods)

or save your self ALL the major problems and buy a HOLLEY comander 960 EFI bolt on and go EFI ststem useing a stealth ram intake for your present engine as it can be laptop tuned to match your set-up (about 550 hp if set up correctly with 32lb injectors without major efi mods)_

 

Do you really need 32# injectors for ~400HP?

 

I currently have a Super Ram on my car. If had to start all over again, I would modify a 4 barrel manifold for FI & use a aftermarket engine management system.

 

LT1 > TPI

 

what about the lack of plenum area on a victor manifold?

will a 2 plane manifold work?

 

2 plane - torque
single plane - hp


then there's hood clearance


Depends on what you want.