im picking up a v6 1988 firebird. im planning on doing a v8 swap to it using either a 700r4 or my t5. what i want to do is use a mechanical pump. so my question is what will i do with my fuel pump in the tank? do i remove it, can it stay or do i need a pick up hose kit? also for the lines up front when i remove the lines from the hard line what - an size is that?

UPDATE: me and my friend will be swapping in the 400 chevy block from his nova and the transmission its a 425hp built engine.

If you power the electric pump and use a factory-type mechanical pump with a return, you'll have a system that is good at preventing vapor lock. A Carter M6626 is a good choice for a performance mechanical pump with a return.

If you don't want to use the in-tank electric pump, there is a sticky in the top section of the Carburetor forum that shows how to convert an EFI pick-up to mechanical pump style. The Carter pump mentioned above is still a good choice.

I can't tell you the factory fitting sizes, but it's been discussed many, many times. Might even be in the EFI to carb tech article.

i found the fuel pump it seems like a really nice pump and its pretty cheap. if i were to leave the gas tank alone and not mess with any of that would i be able to install the mech pump without dropping the gas tank or can i just install the mechanical pump to block then run everything through the regulator and use the return on the regulator back to the return on the stock lines?

Why not just use the electric pump and not worry about a mechanical one?

If you don't have the in-tank electric pump powered, you need to get it out of the tank. It is too much restriction for the mechanical pump to suck through.

Pumps push better than they pull.

Sorry Five7kid.I thought your ref to a search was appropriate.Thing is guy,I read these posts and read them over and over again just tempting me to react.

I agree with using the in tank pump and a regulator lowering the pump pressure.Sure does seem to be the simplest solution.

will the stock v6 electric intank fuel pump support a 500 hp v8?

not the best way, but as far as "simplest" way, just pull through the return line. but make sure you install an in-line filter just like the supply line has, or you will pick up some nasty particals sitting in the bottom of the tank.

Now where did you post until now a 500hp engine and what are the details about that??.

Hey guy,so you're going to build a $5,000 to $10,000 dollar engine using the pump mounted to the engine??. You do know that some cam manufactures do not have a cams to drive mechanical pumps.

the entire cars harness will stay in tach, i will not be cutting anything that doesnt need to be cut. the intank pump will still be powered. but im debating on removal of it and installing a pick up hose kit and new fuel sending unit since it will all be apart

i seemed to have forgotten that key bit of information in the original post. im not building it. me and my buddy were just talking about this. were taking the engine and transmission out of his nova since the body is so badly rusted. its his 425 hp engine that was built professionally with a mechanical pump on the block and his transmission. its a 400 chevy block and a built th350.

trust me i have been doing this a long long time. i have owned many third gens. too many to list in the profile box for cars. i also have my uncle father cousin who have been putting engines together for 30-40 years thats not combined either. not trying to sound cocky or ignorant

Don't think the V6 TBI in tank pump with a reg that has a return line would hold you back.

The factory V6 in-tank pump will support about 300-350 HP, depending upon condition, in a carb'd application. Due to the age of these cars, many have already been replaced, and sometimes (often) the same pump will be stocked for V6's as for the higher capacity TPI application.

As a pusher to an engine-mounted mechanical, it would probably suffice for a 450 HP engine. It would be safer to replace the in-tank with something like a Walbro 255, which would handle the duties either as a pusher, or as the primary pump.