newbie engine question

[doug22]

Hi All,

Picked up a '68 C-10 project. I've done a couple of motorcycles before, but this is my first SBC. It has a bit of an odd setup - 307 block, with a 327 4 bbl intake. It was without the carb when I purchased it. I bought a rebuilt, year correct, Quadrajet for a 327 from Carbs Unlimited. I put it on, but the truck won't run.

I'm getting good fuel to the carb. I cleaned the fuel lines, POR-15'd the tank, replaced the sending unit, and can see good 'spurts' at a clear inline filter.

I did a quick and dirty set of the timing using the marks on the block and I'm getting good spark from the HEI. Though, since it is an oddball with the 307/327 (not to mention the HEI), I'm worried the cam might be different. Not sure how to proceed if that's the case.

I've hooked up the PCV and distributor vacuum advance at the carb. The other two vacuum ports I've capped. At the back of the carb there is a large threaded opening I'm not familiar with...

I've adjusted the two idle mix screws at the front of the carb to 1-1/2 turns out. I haven't messed with the floats yet; assuming they are roughly okay since the carb was purchased as 'rebuilt'.

If I hold the primary choke plate closed, I can get it to run for a few seconds, but it quickly dies if I hit the throttle and let the plate open. It sounds okay and I think it's firing on all cylinders as each header pipe is warm.

I'm worried there are crankcase gases coming out of the filler neck. Not burning oil; seems like mostly exhaust.

Not sure where to go next. Waiting for the battery to charge back up now

Any ideas? Thanks much!