does anyone know the sizeof the holley carb on 86 351 ho 4v?? Or know what holley kit is needed to rebuild, list #502641 thanks

 

It is a Holley 4180 600 CFM vacuum secondary carb.
You want the 3-1346 rebuild kit.

 

^^ This is the correct kit. I've used 2 of them now...

 

Speaking from experience, if you want to avoid idle problems, DON'T use the two-stage power valve that comes with the kit. If you do, you will have to readjust all the idle screws, and you still won't get it to run like it did previously. Look on the power valve that comes out (if original it will be a single-stage) for numbers that will tell you what vacuum rating it is. Mine was a 7.5. A cheap gasket kit is available from AutoZone for about $28. Then go to Advance and get or order the matching power valve for about $9. If you do it right, you will never need to touch the idle screws. Just adjust the primary float and replace the accel pump (adjust according to instructions) and it should run like it did. Just MHO.

 

Maybe that's the problem I had with my old Holley. I used the power valve that came with the rebuild kit. Didn't know any better. If you get the number hwknsdrag please post it. I may order it myself so I can have a backup carb.

 

thanks for the info , local ford dealer couldnt find listing for me. Lavatan I will post the right numbers as soon as I get them

 

There is nothing wrong with the 2 stage power valves in a Holley carb if it's installed correctly and the correct gasket is used.

The power valve has nothing to with the idle circuit, it's shut during this time unless it's leaking around the gasket, or it has a hole in the diaphragm.

 

You can use any Holley power valve in a 4180. Most of the stock 351W will be fine
with a 6.5 or 7.5 single stage Holley power valve.