working on a 383 stroker motor.. brand new Racing Head Service #12301 heads with new weiand stealth air strike #8501 intake manifold.. intake lines up perfectly, the only problem is the huge gap on the end seals.. shop told me to use a thick bead of silicone but i would like some second opinions...

 

i can stack 2 gaskets and it still wont come close.. never seen one this bad..

 

sounds like there is a parts incompatibility or a machining issue here. Thats not normal. was the block decked a lot? the intake/heads may need correcting

 

It's common with vortecs to have a bigger gap than that. Mine was closer to 3/8. I see you're not using vortecs, but just saying that a lot of people get by with the extra thick bead of silicone with no problems. Just make it double wide and a few layers high. Then smear some along the edge once the intake is in place.

I've also heard theres something people use thats more suitable for this than just silicone, but cant remember what. EDIT: In a thread from october, ASE Doc recommended "Right Stuff".

But no I dont think its normal for regular heads to have such a gap.

 

i used to work at a parts store and ive seen the "right stuff". i believe its aerosol and fairly expensive.. if i had to use silicone i was just gonna use good old ultra black but right stuff might be a little better for this application..

but i really dont feel comfortable using that much silicone especially considering the amount of money wrapped up in this motor.. i would like to make sure everythings alright.. so i had an old tpi intake maifold laying around that i set on it, and that made it even worse... im not sure if the block has been decked, but im pretty sure it hasnt.. are there any easy ways to check??

 

Could check the surface on the block in front of the passenger side cylinderhead were the engine identification number is.
Undecked block would have the ID number there and rough surface.

To know how much it was milled, would require to know piston compression hight and then mesure piston to deck.

 

Silicone will work but is garbage for trying to seal such a large gap. The "Right Stuff" is the only thing I use on the end rails.

 

checked the block.. numbers are stamped on there still so that rules that out..

alkyiroc - have you ever ran into a gap that large that you used right stuff on?

 

Gm black silicone works great but you have to let it set for a few hours (I do overnight if I'm working at home) before you fill with coolant/start the engine.

 

heres some pics of it..

 

guess im gonna pick up a can of right stuff and try sealin it up tonite..

 

Even when you watch the car shwos on TV, they take those china wall end gasket and toss them in the trash and use a thick bead of black silicone.

 

I've used the stick-on rubberized cork (with silicone too) china wall gaskets, and also used straight silicone with no gaskets -both with no issues. I personally wouldn't use the rubber type since they tend to slip out of place.

I'm sure any of the methods mentioned above will work if you make sure to apply it properly...

 

With that gap, I would wonder if the ports line up good. What if they are off too? Bad airflow. Bad coolant flow.

 

Yep I learn it all the hard way, trying to use those rubber ones, first set by time the intake was torqued down to spec, they squeezed out.

Had to do it a 2nd time, still not any smarter using the rubber ones again, same deal, carful as can be and they squeezed out, then learned that not even the pro's use them, they goop it too.

Only time I didn't just goop it by default and it bites me in the a$$

 

ports match perfectly.. sealed it up last night.. will let u know how it works out..

 

I had almost exactly the same size of gap as in your pics.

Deck was milled and has summit's 170 aluminium heads on top.

The heads are taller then stock, but ports lined up perfectly. A little thicker RTV black then usual did fine.

 

i never use the end gaskets, i use grey rtv, but if its off alot id be conserned abt the intake runners matching.. i have vortecs on my engine right now and there was abt a 1/4in gap i had no problems using the rtv.. just make sure everything else lines up right..