Sixpack stroker jetingsproblem?

[Kennetto]

I have changed the jets in my 493 before i run 70 in center and 91 outer, now i have 65 center and 78 and 81 outer, but now the engine wont run properly and pops in exhaust, i have had the carbs of several times and can not find something wrong, can it be to small jets?

 

[Bird 426]

I have 67 to 69' s in my 418, depends on whether I run straight premium or regular with 10% alcohol. Your end carbs contribute to idle. I tune idle with a vacuum gauge and finger over the outside airbleeds. Do you have Promax base plates? Read up on how to tune a Sixpack. Google it.

 

[SlinktRR]

I run 73 center and 82/84 outboards on a 499/6bbl setup. Works great. I think something else is wrong like carbs not seated right, vac leak.

 

[Geoff 2]

Bigger engine needs bigger jets. Sometimes......
A popular misconception. A bigger engine creates more 'pull' [ vacuum ] on the jet & more fuel. So there is certain 'self correction' factor there.
More info on when/how the popping occurrs.

 

[Kennetto]

Bigger engine needs bigger jets. Sometimes......
A popular misconception. A bigger engine creates more 'pull' [ vacuum ] on the jet & more fuel. So there is certain 'self correction' factor there.
More info on when/how the popping occurrs.

Sorry for late reply but i give it up for a while, almost sold the car cheap, half summer gone and the car stil in garage but i will give it one more chance, it starts like it should but when i rev it up to 1000-1500 rev it starts popping like pistolshot in the exhaust

 

[oldkimmer]

So obviously it’s too lean if all u changes was the jets. Or u ripped a gasket and have a vacuum leak. You may have a distributor problem. Crossed plug wires? Kim