I have a hypothetical question.

Let's say I have a 1990 Iroc, with a TPI 305 engine. I want to now change motors. I want to put in a Carbureted 400 sbc, to replace the TPI 305. Obviously, I would have to take the TPI system and put it away, or else sell it- or keep it to put back into the car later on.

Well, my question is this: Doesn't the IROC have an in-tank fuel pump? Well, how could I arrange for the new 400 to recieve fuel? I think I would need a mechanical fuel pump, correct? Maybe one similar to the ones used on Carbureted IROCS. Well, how would the fuel get from the tank to the fuel pump? Would I need to hook up lines? Have any of you done this, or something similar, to you car already? What about the in tank pump- would it need to be removed, or would it just sit there and not operate. I hope my questions are making sense. And, how much would it cost to have that procedure done? I mean, arranging for the motor to be carbureted instead of fuel injected?

Also, I want to know specifications on 86-90 IROCS with the TPI 305 engine. Could you please tell me those numbers, if you know them?

I want to know horsepower and torque figures for the following cars: (All with auto transmissions- all in stock form)

1. 1986 Iroc with 5.0L TPI
2. 1987 Iroc with 5.0L TPI
3. 1988 Iroc with 5.0L TPI
4. 1989 Iroc with 5.0L TPI
5. 1990 Iroc with 5.0L TPI

Oh yes, also, what other modifications would be necessary in a TPI 305 to carbed 400 swap? I believe I would need a new flywheel for the 400, right? Are the flexplate and the flywheel one and the same?

What about the 700R4 transmission- would a 400 hook right up to it? Or would changes need to be made. Also, will a stock 700R4 be able to handle the higher torque of a slightly built 400? Initially, I think that the pistons, rods, and crank would stay stock. But, I would probably have a cam, intake, headers, carb, MSD, and high flow mufflers, and a K&N filter. Comp cam, Demon Carb, Edelbrock aluminum int., Hooker headers. I have estimated that the motor would have apx 300 HP and 375 lb.ft of torque with those parts. Does that sound accurate?

Thanks for all your help.

 

well you asked about 70 questions, and i know the answer to a whopping 1. shows how much i know.

not sure if a 700r4 would hook up to a 400sbc, but it definitely would not handle the extra torque, especially since you're building the engine w/ performance parts.

not sure about what trannies match up w/ what engines, but i'd prob. go with a new or beefed up TH400

there, you've tapped out my knowledge on carbed 400sbc's

 

For fuel, a Mallory 4309 or similar (although, the only other one i know is by Barry Grant) return style pressure regulator. Runs for about $75 from Summit. Can use the factory feed line.

Going from EFI to carb is a very common swap. I have done it.

The power figures can be found on the main page, under the tech data section.

Flexplates are for auto trannies, flywheels are for manuals. You would need a 400 fly/flex. They (the 400 engines) are externally balanced and require different parts.

I would build up the 700r4 to take some power. It will bolt up fine.

Define "pistons, rods, etc will stay stock." Does this mean you intend to re-use the 305 internals? if so, it won't work. 400 has a larger bore than the 305. 4.125" as opposed to the 305's 3.735" bore. The crank journals are also different sizes. the 400 has 2.65" journals, your 305 has 2.48" journals. Rods are different,too.

I think that covers the gist of the questions. Anything else, you can do a search and probably find the specific answers.

 

Look in the carb board. One of the top post is titled something like all user read this... or something like that. there is a wealth of info in there about this type of swap.