Alt for liten forgasser hadde nok olds gutta i u.s sagt,i og med eg blir anbefalt fra 800cfm og opp på en 407 olds, høyere komp må vell det være høyere oktan for at det skal klaffe sammen. Du kan prøve å sjenke tanken med oktanbooster og se om det hjelper først.

bruker selv en 800 forgyser på en liten 307 uten problem, men står vell mindre dyser i sikkert.
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I would say q jet 7 days a week, but for a couple of years ago (maybe 20...) i had a '65 skylark with a bone stock '75-76 low comp 455 olds. Ran terrible and needed a new carb. I bought a #1406 edelbrock 600, economy calibrated w electric choke.
Ran like a champ right out of the box. I think a 600 is a very small carb for a 455, but maybe that's what made it run so smooth.
It did have some power too, 20 meters of rubber from a stand still with 3.08 posi and 255/60's. My father in law still talks about the neighbors complaining. Lately I've had an edelbrock 750 on a higher comp 455, but couldn't get it right in any way. Had to take it off and got a good qjet instead. Much better.
/Anders"
Ett anna innlegg..
No less than a 780. I've done multiple 455's on the dyno, at 4000 and above they start pulling vacuum with 850's. What does that tell you. Forget the formulas, go bigger than what they recommend and take the time to tune it right. You won't be sorry.Ett til..
I'm not saying that the ebrock 750 is a bad carb, but i had one on my mild 461 w 4speed, and i put around 1 year of tweaking with rods and jets in that one. Never got i to run smooth in transit between idle and part throttle. Off it came and a rebuilt and recalibrated q-jet was installed. world of difference, runs a lot smoother. The edelbrock 750 sits on a shelf, and i think thats the best place for it.