so i have a 1991 camaro that i put a late 60's motor into should have low 400 hp converted the tbi to carb with a fuel pressure regulator but the only distributor i could get to spark and run was the stock 305 one tried putting an hei one in and a dual point but my major problem is she starts decent if you give her gas you can rev her up but she pops and some times shoots gas out of the carb and she will not idel i think im having a wireing problem is my security key telling my car to do some thing or is their some thing to tell my distributor to advance and retart when it should not i really dont need any computers but she wouldnt spark with out them please help i cant figure this out

 

Wow!

You have a lot of problems, so we'll take it all one by one.

Your original 305 Distributor had an external coil. You want to use the BIG CAP HEI from the 75-80 V8 with vacuum advance, right? Too easy. There is a fat pink wire going to your external 305 coil. Test that wire with your voltmeter, and make sure that a full 12vdc gets to it when the key is ON. This is the wire that plugs into the HEI cap to run it. This is all that is required to run that older style HEI.

So, with THAT out of the way, we turn our attention next to fuel delivery. Your stock in tank pump cannot handle the fuel volume that you need. It can barely support a stock TBI engine. It is not a matter of fuel pressure really, it is volume. This is the worst electric pump that GM ever used, and you will run out of gas at high rpm in your carb engine with 400HP.

You have two options; You must drop the tank and pull the sending unit for either. You can either replace the sending unit with an 82-87 carb sending unit and then run a mechanical fuel pump on the block (or external mounted electric) or you can install a high performace fuel pump in the tank and keep using your regulator.

I prefer the electric in tank unit. I like the factory pump for the 89 Turbo Trans Am (also used in the late 90's in the Vortech V8 engines in the pickup trucks.) Vin code 7. That pump easily supports 400 HP, I have done it before.

 

Is there a difference in 91 tbi fuel pump and a 87 2.8 efi fuel pump? Am using the stock in tank pump on my 383, seems to run just fine

 

i did hook the pink wire up to the hei and the dual point with an msd coil i had and it had weak to no spark also the tbi needs a lot more fuel pressure or volume doesn't it? thats why i needed to the fuel pressure regulator to bring the pressure down other wise it would push right past the floats could i just run a switch to the ignition to have the fuel pump run all the time to get the volume i need?

 

I ran a switch for my intank pump, it would shut off after carb got filled thhen I would run out of gas. I spliced into the line under the carpet and put it on a switch. I have no problem with stock v6 fuel pump feeding a 450+ hp 383 carb

 

First off, YES there is a HUGE difference between the mpfi V6 engine and the TBI V8. The mpfi V6 is actually a decent pump!!

The V6 pump puts out 41-47psi and a decent fuel volume. The TBI pump usually struggles to make 12 psi. You can run SOME carburetors at 12psi, I mean, that's low...

Go back to your BIG CAP HEI. If you were using the pink wire, fine. CHECK it with a voltmeter. Something is wrong. You should have a solid 12 volts at that plug when the key is ON and 14+ volts while the engine is running! You will not get weak spark from that!

Make sure you have a FAT ground going from the engine to the frame, and the engine to the firewall. If your engine block is poorly grounded, your stand alone distributors (points or HEI) will not run well at all. Your factory one can ground back through the harness, although that's not good for it, but it does ground the coil back through the harness. I suspect THIS may be your ignition problem.

I suspect you may have more than one pink wire under the hood. Maybe the wire has been repaired in the past and the one you need is Orange, or Red. My point is that one of the coil wires is really fat, and it should have 12 volts at the plug when the key is on.

Find that wire and the ignition problem is fixed. Then on to the fuel...

 

Thanks for clarifying the pump. Now question is I thought carbs run around 6.5-7 psi.

 

Most American carbs do. Some euro/asian carbs run high, in the mid teens. Its just a design thing.