In my gasket set I have two different intake gaskets, one has both front and rear coolant passages open while the other set blocks off the rear coolant passage. I can't remember what was on the motor when I tore it down, does anyone know which one I need to use? I can post a picture tomorrow if you don't know what I'm talking about here.

Also, my new Hedman headers do not have a O2 sensor bung so I'm going to have the exhaust shop install one on my Y-pipe. Would it be OK to run the break in on this new motor without the O2 hooked up? Or will my computer flip out? Seems like it would run in open loop correct?

And one more thing, I'd like to block off the EGR port on the intake under the plenum. Will that affect how the car runs if I deleted it? I will be getting a tune as soon as I get the car running, alignment completed and exhaust welded up.

Thanks

 

the tpi intake on f-bodys dont use a coolant crossover like edelbrock, tpis, accel and corvette tpi base plates. If you are going to run headers you should install a heated o2s so the car can go into closed loop/ The egr delete you may get a code 32 so it should be reprogramed out of the memcal.

 

Did you ever find out which intake manifold gasket to use? I'm looking for the same answer and I also have a 89 IROC. If it helps I can tell you that the rear coolant ports were blocked on the gasket that I took off. I've got Edelbrock Aluminum heads on mine, and it just occurred to me to call Edelbrock about this. Nobody answered your question and I'm not sure who else to call. I was going to leave it unblocked but I'm really not sure which to do.

 

Is there a coolant passage across the back of the manifold? If not, then it doesn't matter which gasket you use. If there is, use the gasket with the holes.

 

Only aftermarket and corvettes intakes use a coolant crossover.

 

Are all the GM lower manifold gaskets the same? The only one I can find is ACDelco 10159409 and I can't find any specific listings for TPI manifolds. I have an 87 LB9 305 TPI and it's getting to be a pain to find TPI specific parts now. I used to see kits with the upper gaskets and lower gaskets but the Felpro kit I bought only has the uppers.

 

I think there all the same. felpro 1204