Blocking nailhead heat from heads to intake.

Rebuilding 401 for 65 Riv and shes ready for initial start up. Reading some threads im seeing people giving alot of negative feedback on blocking the heat from heads to intake. Which is what i was told to do from faso when I got my gasket kit. This car will be a fair weather driver mostly in the 70 to 90 degree days. Im wondering what people know from experience more then copy and pasting others responses. Should I remove them to properly tune and time my ride so to take out any issues they may cause out of the startup debugging process.

 

Check out www.nailheadbuick.com.If you can't find the info you need,than give them a call.

 

The heat riser is, of course, an aid to cold driveability; I blocked it off on one car,....and a week later, unblocked it, due to poor "off idle" acceleration. I was in a warm climate at the time, btw.

4TTRUK

 

Get a 66 Q-jet intake, set it up to run electric manifold heat with a Qjet, best of all worlds.



You need a temp switch and a relay.

 

I have plugged the two holes in the carb base on the last two nailheads I have run. Mainly to eliminate exhaust leaks under the carb and to eliminate the need for the stainless steel divider under the carb. The engine gets up to operating temp pretty quick but the idle quality is poor until the engine has run for a while longer. After about 30 min or so everything is fine.

 

Don't block it off, restrict it to 1/2 holes. Use a working manifold heat control valve and trim 1/8 around it's edge.
Make sure you have the stainless gasket under the carb.

Use a anti- radiant heat coating paint under the manifold.

Be sure you have a balance tube or H pipe so you don't have an unbalance that makes the exhaust flow thru the manifold when hot.

 

Blocking the exhaust in the intake should not give any serious side effects. It may take a few more minutes before the car runs ideally-as in all warmed up, but nothing to be concerned about.
On the first 2 single carb iron intakes I ran, I blocked the ports. First at the top of the intake to keep the exhaust gases from the carb base, then at the gasket side.
Now I have the exhaust fully blocked in the heads-no flow from the exhaust ports to the intake at all. It takes a little to get to temp but with the other mods I have done this is hardly a concern.
Carmen Faso is a straight up and knowledgable Nailhead guy, as are Tom Telesco and Russ Martin. Most of the information these guys offer are very similar, nothing too trick and no BS. Tried and true modifications.