If you dont have a heat riser it doesnt really matter if the crossover is closed or not.When the heat riser is installed,when the car is first started the closed valve will force hot exhaust through the crossover to the open side exhaust manifold.With no heat riser some hot exhaust will crossover but not nearly as much as when the riser is in place.The heat riser is used for faster engine warmup.Once the valve opens not much hot air is forced through the crossover in the manifold.I would block the crossover but thats only my opinion.Anyone else have any input? 

  

I do not have the heat riser any more. But I do drive the car sometimes in cold weather. My choke is manual, connected only to the choke plate (not throttle). My question is, should I be blocking off the passages at all?

Joey,Do you still have a heat riser valve installed or a spacer?The heat crossover passage works with the heat riser valve.You can use the stock type gaskets by using tin or aluminum to block off the passage.Put the  blockoffs under the gasket against the head.

  

I blocked off my heat passages with thin tin when I swapped over the the B type manifold on mine. No more paint discoloration. But I also am running an electric choke.

Brian - 56 T-Bird

Woodinville WA

Hi Mark. You were right the first time--PCV valve which vents into the carb port, and the oil fill cap is also vented. Got rid of the old road draft tube. My grommet for the PCV is a pretty decent fit, the rubber is still good, and the little assembly is held in place with a philips screw.

Anyway, I was thinking about blocking off the heat crossover passages. The paint is burnt off the underside of the manifold. But I do drive the car in cold weather, long as it's not snowy, it's cold here for a lot of the year. I would like to hear more input on that. I have already bought intake gaskets from Mac's, they're just the regular ones for a TBird without any blocking part. I guess I could cut some thin gauge steel so it doesn't interfere with the gasket fit. But I wonder if I should be doing it at all...any ideas...?

joey

Looks good.I assume you are going to a PCV valve with that pan.A suggestion.You might want to glue the rubber grommet to the pan before you go further.The grommet tends to pull out when you remove the PCV valve and its a fight to get it back in because its an awkward spot with the intake on.This suggestion worked for me.Are you going to block the heat crossover passgae from the head into the intake?Keeps heat off the carb and your intake wont burn the paint off.OOPS!I just realized you have a T-Bird.I guess you are going to hook up the draft tube to that opening in the pan not a PCV.

  

Good tip--thanks. I will.

Use some thread sealant on the studs and bolts for the intake.


Lawrenceville, GA

Upon advice gotten here, I cut about a 1/4" off the top inch or so of the valley pan. Did a dry fit and it slid right into place. Put some gasket sealant/adhesive on the surfaces and installed it, snugging up the two bolts. No sweat.

Before and after pics below. I think now as long as I have the manifold out, I'll touch up a few areas with fresh paint. Thank you gentlemen for your input.

 

Joey

I have been able to put the valley pan back on without removing the heads. You just have to move it around a bit.



In the past, I have shaved about a 3/8 on an inch off the sides of the baffle. That helps, although the last time I didn;t have to do that.



Check the gaskets under the bolts that hold the valley pan to the block. Frequently, these are very thick. Cut about 1/2 off to make them thinner. This also prevents the intake from hitting the bolts.

54 Victoria 312;  48 Ford Conv 302, 56 Bird 312
Forever Ford
Midland Park, NJ