Hey all
I have gone through most of the normal routes to try to solve my problem and not much has changed. Here's my set up
Gen I Chev 355
Forged rotating assy
flat top TRW's
Vortec 062 heads, full port/polish, valves cut, new springs/retainers etc
Lunati 60103 hyd flat tappet - adv dur @ .050 268/276...Lift 489/504...110 LSA
Hedman full length headers 1 5/8 to 3"
Edelbrock 1411 750cfm elec choke
Pertronix Flamethrower HEI - 18* initial - 34* total in at 3k
Champion rs12yc plugs
Built the motor from the bottom up, runs great for the most part. But if I hit the accel hard I get a hesitation. It is a quick and hard bog before it grabs and goes all the way through the rpm band. It doesnt matter where in the rpm range I hit the pedal, still get the bog before it picks back up, but only when I slam the pedal. For example, I rev to 2500, then let off the gas and quickly slam back on the pedal, it will give a bog and fall on its face for a second before it picks back up. It will rev fine through the entire range when its gradual, but that initial hard slam on the pedal is wreaking havoc.
Initially it was very bad, and even backfiring through the carb. That was a timing issue on the first couple start ups, it was too far retarded. Ended up with the best results at 18* initial with this cam and it solved a bit of the problem. Generally speaking I would expect this to be a quick lean condition, so I grabbed a calibration kit, changed the springs to the lightest they have, raised the accel pump to the highest it can go, swapped rods up and down and still the same problem. Tried the lightest and heaviest springs, changed the pump shot to the highest and lowest settings, bumped the timing up and back a few degrees each way, changed the rods to richer and leaner, still the same issue. I have only used an Edelbrock once before and had nice results, but that was on my old stock 350. I am wondering if there is something that may be escaping me here, or if maybe this carb is out of its league. It is brand new out of the box, so not like it was used or tinkered with before.
I would have thought there would have been noticeable changes in the problem with all the adjustments I made, to make the problem easier to detect, but no such luck.
I also have an Edelbrock plate NOS system hooked up, but havent run it on the new motor yet until I can get it dialed in right and this issue resolved.
Any help from any of the gearheads here would certainly be appreciated,
I have gone through most of the normal routes to try to solve my problem and not much has changed. Here's my set up
Gen I Chev 355
Forged rotating assy
flat top TRW's
Vortec 062 heads, full port/polish, valves cut, new springs/retainers etc
Lunati 60103 hyd flat tappet - adv dur @ .050 268/276...Lift 489/504...110 LSA
Hedman full length headers 1 5/8 to 3"
Edelbrock 1411 750cfm elec choke
Pertronix Flamethrower HEI - 18* initial - 34* total in at 3k
Champion rs12yc plugs
Built the motor from the bottom up, runs great for the most part. But if I hit the accel hard I get a hesitation. It is a quick and hard bog before it grabs and goes all the way through the rpm band. It doesnt matter where in the rpm range I hit the pedal, still get the bog before it picks back up, but only when I slam the pedal. For example, I rev to 2500, then let off the gas and quickly slam back on the pedal, it will give a bog and fall on its face for a second before it picks back up. It will rev fine through the entire range when its gradual, but that initial hard slam on the pedal is wreaking havoc.
Initially it was very bad, and even backfiring through the carb. That was a timing issue on the first couple start ups, it was too far retarded. Ended up with the best results at 18* initial with this cam and it solved a bit of the problem. Generally speaking I would expect this to be a quick lean condition, so I grabbed a calibration kit, changed the springs to the lightest they have, raised the accel pump to the highest it can go, swapped rods up and down and still the same problem. Tried the lightest and heaviest springs, changed the pump shot to the highest and lowest settings, bumped the timing up and back a few degrees each way, changed the rods to richer and leaner, still the same issue. I have only used an Edelbrock once before and had nice results, but that was on my old stock 350. I am wondering if there is something that may be escaping me here, or if maybe this carb is out of its league. It is brand new out of the box, so not like it was used or tinkered with before.
I would have thought there would have been noticeable changes in the problem with all the adjustments I made, to make the problem easier to detect, but no such luck.
I also have an Edelbrock plate NOS system hooked up, but havent run it on the new motor yet until I can get it dialed in right and this issue resolved.
Any help from any of the gearheads here would certainly be appreciated,
