Need carb spacer/adapter advice.

[mabeauchamp]

I've run into a snag with the new Moon valve covers and roller rockers. I am running a stock 340hp intake with a 1407 750cfm Edelbrock. Because of the additional height roller rockers and valve covers, (forgive the gross error in terminology) the "carb linkage on the opposite side of where the throttle rod meets the carb" is hitting. I need to install a ~1" spacer. It can't be anymore than that because I'll run into clearance issues with my air cleaner.

After researching old threads it's not clear if I need an adapter the way the 2x4 set-ups do to take care of vacuum leak. I don't think I do. Will any 1" spacer that will fit the Edelbrock carb work?

 

[Impalaguru]

Luckily your 340hp intake has the larger holes so I would think that any square-bore spacer should work. Pay close attention to the bolt pattern. Make sure it has the holes to mate up to the "tighter" pattern on your 340hp in take. I think your Edelbrock has both patterns. There should be 2 holes on each mounting "ear" on the carb.

One other thing. On my old 409 I was running a 340hp intake and a carter AFB from a 300hp 327. With just a gasket between the carb and intake my fuel would start to boil. I added the stock bakelite insulator and stainless steel shim and that too care of that problem. It also moved the carb up enough so that the choke didn't hit the pass. side valve cover. That insulator and shim(with gaskets) was about 1/2" or less. I think you can get the insulator and shim reproduction from Corvette suppliers. All 300hp engines with the iron intake and aluminum carb used this set up. The rochester 4-jet (stock 340hp carb) had a cast iron base so I guess this wasn't an issue. I have a similar set up on my 340hp 409 but the holes form the exhaust crossover ( in the carb mounting pad) are stuffed with steel wool. I am running stock valve covers. No heat problems.

Best of luck!!

Ross

 

[mabeauchamp]

Ross, Thanks for the info. That's exactly what I needed. Mark