Update to previous post.
Apparently my notes were the stock injector numbers. I went and checked injectors, we used Bosch 0280150991 as replacements for stock

cool, thanks for the info.

Have to ask your experience with fuel injectors and did you test the flow rates because Bosch 706 and Bosch 991 do not even flow the same amount - flow rate = cc / min -

Marren fuel injection(injector.com) did the work they are local to me. I was told they flow tested old and new injectors.

After doing some research based on your comment. I have to say mr Bup you might just have answered a question that's driven me crazy for years.....I chased my tail with those engines and gave up, always thought it was ignition or some problem with ecus. Since I did not have access to the tester I could not go any farther with them. After knocking top ring land out of a fresh rebuild I punted. It "can't be the injectors I spent almost 2 grand testing and replacing them" nothing like leaning them out with a too small injector DAMN IT!!!!! Never checked flow rates trusted a pro.........

hence my reason for post #2!

Aren't the 991's a 24# injector as well? Or are they rated at a different pressure?

These Lucas;s ?
http://www.fiveomotorsport.com/lucas...-1985-1986-5.0

I know for a fact that they will not even flow the same amount of fuel running apples to apples testing (persay) . This is why I just stick with marine fuel injectors. I have all the data and so on for the marine side only., If you are doing ALL fuel injectors - cars, trucks, drag stuff, bikes go carts, PWC, boats and so on that is way to hard to keep up with all of that.

It cracks me up the cars guys who think they know how marine fuel injection works to a T right off the bat and they can get right into the ECM and start changing cals. I gave one big time car tuner a look at the engine with PCM 555 and the DLC then told him, lets mess with the cal - the first thing out his mouth was what F is this. I said exactly. But the other side of the coin is, I really do not know much about the latest auto stuff nor all that injector data and fuel pressures and so on.

Anyways I repeat again - it is best to run the full testing of the original fuel injectors after you know that have tested good and then match up what will work using current offings especially if the original injectors are EV1 and or GM MULTEC injectors.

IMO GM Multec fuel injectors with sometime on them are one of the worst fuel injectors, some are still installed in marine apps. These injectors were used in the 90's application for some of the MPI systems. Not all but some. I just got 8 in the other day. Not even going to waste the customers money and test them. Just going to sell him brand new current offering.

I had one of those 320 motors back in the day , long story short , the best thing we did was take that injection off and put a new intake and 4 barrel holley and motor worked great for years.... that motor was a 300 tempest with efi...