Ok thanks, I wasn't trying to make you guys repeat already stated info, so sorry for that. Just wanted confirmation.

Will the 57+ manifolds work on this motor? or are modifications required? And do the 57+ manifolds accept the "modern" holley 4150 carbs? This is just for future reference in case the adapter i bought from Thunderbird Headquarters doesn't work like I want it. It adapts a 57+ carb to the earlier manifold.

The '57 + manifold will bolt up but you may have sealing issues as the ports may not line up exactly with the head's ports. It will accept the Holley 4150 and other carbs without needing an adapter. I suggest using a phenolic spacer to keep the exhaust the heat from the crossover passage from boiling the gas out of the carb.

Would you suggest that if I use the adapter I mentioned too?

You shouldn't need the adapter for the '57 and later manifold. The adapter is only needed when installing a '57 and later carb on the '56 and earlier manifold due to the mismatch of the bores in the manifold to the carb's wider spaced bores.

How I meant to ask is, if I go with the adapter route, since it's already shipped, vs finding a later model intake, would you still recommend a phenolic spacer? Or would the adapter serve that purpose?

This isn't going to be a hi-po set up. Just trying to get it starting and running reliably.

Some sort of thermal "break" is a good idea if you wish to avoid a situation where fuel is boiling out of the carb after shut-down. It doesn't have to be huge in thickness to do the job - Edelbrock used to sell a 3/16 thick gasket (for the later Holley pattern) and that often cured the boil out on those. Maybe multiple gaskets clamped under your adapter will do the trick? Just be sure they aren't hanging out into the bores.  




 
 Steve Metzger       Tucson, Arizona

I use an adapter on my '55 Merc only because it still has the original intake manifold and I'm running an Edelbrock carb. The adapter will not solve the fuel boiling issue since it's made of aluminum, so I also use a 1" phenolic spacer between the carb and adapter. No issues with boiling fuel and a side benefit is snappier throttle response. I'd recommend a phenolic spacer even if the carb and manifold match without an adapter.

Thanks a lot!

The only issue with spacers is hood clearance - you want to make sure you will still be able to close the hood.

I'm fairly certain phenolic spacers are available as thin as 1/4".  If you are using a 4 hole adapter, then you also want to use a 4 hole spacer and ideally, you want to blend them together so that there is a smooth transition from one to the other.


Lawrenceville, GA

You can block the Heat crossover with a piece of Tin when You have the Manifold off if you do change the Manifold. The crossover was needed in cold Weather to warm up the Manifold faster. That and a Phenolic Spacer solves a lot of the problem.