Thanks Tom, but it is not a square bore carb. I have spent several hours on the phone with Summit, Jeggs, Trans-Dapt, etc. So far,it looks like I am going to buy a blank, 3/8" thick piece of composite and make my own. Thanks again, FrankI found this Canton Racing Products one on Summit for square bore carbs Canton Racing Carburetor Spacers 85-154
Doesn't say if it fits both Holley and AFB. I'd call and ask.
Do you have the intake manifold carb heat passages blocked? I have read where some with 340 horse engines had drivability issues after about 20 minutes of drivingwith both sides blocked. Others say no problem. Some suggest only blocking one side. I have has AFB cars on both aluminum and iron intakes with the heat passzges blocked and never had a problem with drivability.
Many aftermarket performance intake gaskets come with the heat passage block off plates. I see some in Summit have them and some don't.
check the following link as he advertises he has one available
Carter WCFB Insulator
This is usually the one that is used.
On Saturday, June 16, 2018, Frank <firstname.lastname@example.org> wrote:
Hello. I have a Carter # 3461S, Corvette, 340HP. Will your CAFB 250 fit this? CC across front mounting holes is 4-1/4”, front to rear is 5-1/8” Thanks, Frank