Engiine misfires

[echappe]

OK Gentlemen start your engines,
I have just completed 3.5L swap 110,000 mile engine had nice golden glow inside with no sludge , head was pulled and valve job completed with new guides and stem seals. It was put back together with new ditributor, plug wires, new weber 38/38's, etc. Fired up on first try and idles well. At about 4,000 RPM's when I put my foot into it, it stumbles. Does anyone have any suggestions or pointers of where to start to try smoothing this out.
Thanks
Ernest

 

[sfdon]

For what it's worth...

Stumbling going up the revs is lean

Stumbling on the way down is rich


On every 3.5 engine I install, I include an O2 sensor- at least get a 3 wire heated sensor and drive 50 miles with a volt meter attached.