My first tread. I recently installed a 383, 9.9-1, 1.6 roller rockers, cam 110 degree lobe seperation, 4.88-4.90 lift, 226-228 at 50 degrees. Edlebrock tbi manifold, CFT Tech splacer with cut down divider between barrels. Dart s/s fastburn heads, 165 runners 67cc, 1.94 & 1.5. Headers 3" performance cat, head pipes into single 3" exhaust with dynaflow 3" truck muffler, single exhaust. K&N 14X3" flate base aircleaner. 8 degree initial advance. 5spd manual truck trans. I wanted more power for my truck (93gmc 350) for towing a 29ft house trailer. This was a crate motor and was advertised and 427 hp at 5500 and 468 torque at 4600 all blue printed and heads mildly ported for better flow. These ratings were with a carb setup.
I knew nothing about TBI and purchased this set up. I installed it and fired ritht up. After beaking it in. It ran like crap. I took it to a dyno shop and they put in 65 lb injectors and told me the best they could get out of if was 207.51 hp at 4000 rpm and 297.51 torque. at 2300 rpm at the rear wheels. This was without the tbi space which I put in later and noticed some difference in the low end. It runs a lot better after the dyno.
The problem I have is that between 2100 and 2600 rpm's under light trottle pressure in 2nd gear it surges. If I increase the trottle pressure or stand on it, it runs fine. Does it need more fuel, am I expecting to much from this engine? How can I increase the HP and still have decent mileage? My mileage on the freeway is about 18mpg and in town about 12-13.

One more problem I have is, if I hook up the egr valve it surges and seems to miss continually at crusing speeds of 25 to 50 mph. I did try puting a new egr valve in it but the same thing happens. Runs great without it.

I am towing my trailer this week end for the first time. I sure hope that it has more power and gets better mileage than my old 350. Any comments would be appreciated.