Intake gasket questions

[Chrispbrown36]

I have searched the forum and still can't seem to find a straight answer on this. I originally changed my intake manifold gasket with a Fel-Pro gasket that did not have the block off plates on it. Now I am looking to change it out again hoping to seal up some leaks and I am wondering if I should go with one that has the block off plates. Some say that the block off's only help with an aluminum intake but not a factory cast iron one. Some say that it's only necessary in colder climates. Some say it's not necessary at all. My thinking is that the original gaskets had the block off's and the engineers had a reason for it....so you should do the same, but I would like to see what you guys think. Along the same lines, everyone says to use the Fel-Pro gaskets, but isn't an AC Delco a better choice?
Truck is an 87 V10 TBI 350

[Gregski]

forgive my ignorance but block off plate for what the cross over exhaust gasses? if so then I would always block that off since colder intake manifold is better for fuel mixture since colder air is more dense, and every bit helps

as far as gasket brands, the best Felpro intake gasket I have found only comes in a complete kit and they do not sell it separate, let me see if I can find the part number for you

part number: 98000

[Gregski]

if you decide to not block off than this Felpro 1256 works well

[Chrispbrown36]

These block off plates are on the rear coolant passages. Like this.....

[Gregski]

Originally Posted by Chrispbrown36

These block off plates are on the rear coolant passages. Like this.....

oh, the coolant ones, but there is no hole in the intake manifold right, so it really makes no difference?

[Chrispbrown36]

There is on a TBI intake I believe......

[cadillac_al]

Hmmm, learn something new every day. I have never seen gaskets with those block offs. LT1 gaskets maybe?

[Jake Wade]

Victor MS15401. If you have TBI, you need this gasket or the equivalent in a competing brand.

[Chrispbrown36]

Jake, that is the same as the AC Delco one with the block off's. What is your opinion on blocking off the coolant passages vs. leaving them open?

[Jake Wade]

It will run hot if you use the older style for carb applications with the open passages at the rear.