Well I had Bosch injectors on the last engine so I figured I'd try out some Lucas ones this time. Anyways the 383 dynoed with a carb at 532hp/482lb ft at the crank....now it's Minirammed with a new Walbro 255 fuel pump. PROM tuning will all be done by myself....gonna hafta learn alot!! She's a nice day, weekend car that'll be taken to the track occasionally. The guy at Racetronix says to go with 42lbs running them at 80%....I did the calcs too and it seems like that's the case....although it seems alot of people with 383's (with 400-450hp) are running only 30lb injectors.....
PLZ help....Seems all the formulas point to either 38 or 42 lb. ones....

- Joel

 

On a slightly milder Minirammed 400ci I ran 32# injectors and they still had a little "headroom" left while laying just over 400HP to the wheels (around 500 flywheel). Our combo had a HP peak around 5000 RPMs and was never revved over 6200.

I would think that your combo would get by with the smallest 36# units with no problem. However, I doubt that going a bit bigger (even up to the 42# units) is going to cause much of a problem. In theory too big an injector will get "weird" on you at idle where very little flow would be required. Duty cycle gets VERY short and the injector just can't reliably feed an accurate amount of fuel at such a low duty cycle. That's the theory anyway. Our motor idled exactly the same with 32# injectors as it did with 22# units (with appropriate changes to the chip's injector constant variable). No noticable difference.

Obviously, custom programming on this is absolutely required given how far from stock everything is.

 

Thanks for the info! Yeah I'm thinking 36's would work well....or maybe some 38's........42's just sound way to big to me....even though the forumlas show that.....I'm not going to be redlining all too often or taking it to the track every weekend....

Thanks,
- Joel