k&n

would a clogged air filter (k&n) cause my engine to start missing at about 3500 rpm when it runs fine at 3000 rpm and below?

 

It's possible, take it off and see

 

The K&N filters can also be over oiled very easily. Learned that from experience with my race bikes. Cleaned and oiled the filter before a race and the bike wouldnt get colse to redline. Took the filter out and it ran fine. So I immediately recleaned and oiled it properly. Bingo!

 

bought another filter to run while i cleaned this original. still running like junk. decided to tune the carb. oh my god what a difference. now, should a 460 idle at 1000-1100 rpm? that's where it sounds the best and it ran really well on the short run i took it on. just seems a tad high. any thoughts?

 

Seems way to high,especially if it's not cammed up.Mine idles around 550-600 rpm's.

 

at 550-600 it sounds like it's missing. if it has a cam i don't know what it is. i bought this truck off of a guy that bought it off of a guy.
it has a performer rpm intake and big headers and the dove-c heads from a 69 or 70 lincoln. i feel like it may have at least a small cam.

 

Maybe one of the idle circuits in the carb is plugged. That would make you have to open the throttle farther and make the main jets come into play to make it run smooth.
I'd pull the idle jets and spray carb cleaner in the p***ages or just overhaul the carb.

 

i'm thinking the carb needs to be re-built. i've got it down to around 800 and it's just short of surging. runs out pretty good but not quite as strong as it did a 1000.
edelbrock says to use the 800 cfm carb with this intake and this is the 750. i'm thinking about shelling out the cash for the new carb and just hanging on to this for a back up or the next big block.

 

I'd rebuild it. The kit isn't awful expensive and these are the one of the easiest to rebuild. And 750 cfm's is more than enough for that engine. Edelbrock's website has very good info on tuning these carbs also.

 

did a little cleaning and re-synched it and got it down in the 700 range. drove the snot out of it yesterday and i'm going to pull a couple of plugs today to see what they can tell me.