Quick run down. Engine ran great first race of year. 2nd race during main, get hit,which causes a flat and forced to infield. Get fixed and go back on track. notice a miss so call it a nite.

What could it be? Maybe valve springs? Put new ones on. Same thing
Changed distr., plugs, wires, fuel pump, solenoid, checked timing and all electrical connections, compressions good. floats good,changed the oil, it was clean, cut open the filter in was clean. Idles fine, and sounds good until the 4200 area.

Drove it up and down the road and noticed when it would start to miss if let of then got back on it it was fine.

Could it be the fuel pick up? A hose collapsing?

Talked to a bunch of guys, that's why we changed everything above 1 by 1.

Anybody have this before?

Thanks Wood for the input. Put a brand new Pro Form distr. In. Still got the miss. I'll check the wiring closer.

Have the battery checked for a dead cell. Had the same problem only missed under a load and wouldnt turn more than 6400. Changed every thing but  the block twice. battery was brand new and had a dead cell. After buying new cam,heads carb and two distributors found the problem by accident.

Tried a new high volt coil and module in the old distributor, did our first run, no miss sounded smooth. Turned around, our second run the miss returned. Put a brand new optima in. Still got the miss. We finally had a smooth run. That was encouraging.

Thanks Darrel and JP for the advice. Good to meet you too Goldstar.

Gonna check fuel line tomorrow. Blew them out today, maybe collapsing under load?? Very frustrating.

I chased that problem for over a year .... Seemed the stock fuel pumps werent keeping up. Put a holley fuel pump and a regulator on and problem went away. But, also, check your breather on fuel cell, and if your line is rubber, change it every year or add a steel line instead.

Update.... Looked at all the wiring under dash. Found a couple wires connections loose. Installed a brand new tach and push button. New fuel line and still got the miss.
Did a leak down all cylinders were fine.
Gonna try a better flowing fuel pump. We usually run the stock one with 3/8's hose. Gonna run 1/2" like Leeboy suggested.

To be continued....

Danny, what plugs do you have in the motor?Give me a call when you get a little time and let me ask you a few questions.  Matt
(209) 761-8328

Another thing that happened to me, was over the winter, the rubber fuel pick up actually rotted part way up. As well as some of the fuel cell foam. And the rotted fuel cell foam, clogged the fuel line partially. Try blowing out the fuel line and try and catch anything that comes out( if anything comes out )

Tim this is Mike, Dannys brother. Are you saying to go up on the jets?
I'll try it tomorrow.  thanks.

Matt , we had the 133's in. Went to the ar26's. Had a new set already. I'll call you on Monday. Thanx.

Ian, pick up is in the RR corner. Got hit in the LF.

LeeBoy, there is no foam. Already blew the hoses out. We now have new hose from ful pump to cell. Thanks for the help

How can a hit in the LF cause this problem?? Just a coincidence??

The only thing that has to do with fuel, or electrical we haven't done is the bigger fuel pump and hose.

To be continued..

Danny, check the pickup and make sure it didn't move on you. Cut the end of the pickup on a 45 degree angle and position it so it can't suck to the cell. Make sure the tip over valve didn't come apart and trying to suck the pieces into the pickup. Also make sure all vaccum caps are on carb, and make sure they are good with no cracks.

Hey Bill this is Mike posting.we didn't go down to the pits, we were in the stands..  Put a new bowl and float on. I'll let you know if that helped. Everything in cell looks good. Took apart, and pressurized the pick up to see if it had a small hole. End of pick up is already a 45 . All vacuum caps are good.

Kelly, we have never ran a ground from block to frame. I'll put one on.

Thanks guys for all the help.

Mike