Here is the Chinese one that is 70mm.
Professional Products 54151 - Professional Products EFI Intake Elbow Adapters - Overview - SummitRacing.com
And the not Chinese one that is 75mm. BKK and Edelbrock also make them.
Trick Flow Specialties TFS-5150SN95 - Trick Flow® SN95 Throttle Body Adapters - Overview - SummitRacing.com
The only truly effective way to lower the compression ratio is to change the pistons. Everything else doesn't make enough difference to be worth it. I would just leave it the way it is, or if you are dying to get more power out of it, throw the nitrous at it. If you boost that big 408, be ready to drop about $6K on a transmission, and $2K on a rear end.
Kurt
Professional Products 54151 - Professional Products EFI Intake Elbow Adapters - Overview - SummitRacing.com
And the not Chinese one that is 75mm. BKK and Edelbrock also make them.
Trick Flow Specialties TFS-5150SN95 - Trick Flow® SN95 Throttle Body Adapters - Overview - SummitRacing.com
The only truly effective way to lower the compression ratio is to change the pistons. Everything else doesn't make enough difference to be worth it. I would just leave it the way it is, or if you are dying to get more power out of it, throw the nitrous at it. If you boost that big 408, be ready to drop about $6K on a transmission, and $2K on a rear end.
Kurt

. besides speed I am wanting something not seen to often like twin turbos lol. There is probably a reason I dont see too many that way though. I like the nitrouse idea though. I have thought of that as well and im wondering if that new nitrouse plate for carbs from ZEX would fit under the elbow? Never the less I will just start with his motor and have fun with it first. Who knows I may just be happy the way it is 


