Has anybody noticed that once they set down their intake the bolt holes at the 4 corners seemed to line up just slightly less than perfect?

I set mine on a 305 long block sitting around and it apeared (without gaskets) that the bolt holes line up just on the very bottom of the holes inthe intake, adding a gasket would only seem to compound this....

Im not concerned about getting around it, I just dont want to use the corner holes as a reference to drilling the rest of them if they are in fact slightly off?

 

Yes, they don't actually line up. Since the angle is different this makes the bottom of the hole move outboard and thus all the other holes if you use this as a reference. Basically, all of the holes I drilled were wrong. I am sure you can find an easy way to compensate. And I am not OK with you deleting this post.

 

I was thinking of lining up the intake ports on a 1205 intake gasket and then drilling the holes in reference to the gasket holes from there.


Millican/RCR how are you/did you do/doing this?

 

I went by what John originally said, that they do line up and drilled from there. Once I tried to line it up, then I realized my mistake, although I thought my problem was due mainly to having my heads milled. I ended up sloting the holes a bit to get it to fit. It wasn't pretty, but it is effective.

 

Ahh..

well maybe to help misguided individuals following johns howto there is a possible update due? Something to the order of "The four corner holes are close, but not right"

So RCR if you had a new LT1 intake to play with, would you line the gasket up to teh intake ports, then mark the bolt holes in the intake according to the gasket?

I think thats what I may do

 

tpi_roc:
That's a good question. First off, it's a lot easier if the engine is on a stand so you can walk around it and get a good look. The difficult part is that you could line the gasket up to the intake and drill the holes, but that does not guarentee that the intake ports line up with the heads. If I had to do it again, I would glue the gaskets down to the heads, using an old manifold, then try to line them up on the LT1 intake, transfering them with ink or something. There's probably a better way, but it's too early right now to think of it.

 

Well apon thinking about it more...

If I simply line up the intake ports on the gasket perfect, then drill a hole at the correct angle from the bolt holes on the gasket, when I set it in place on the engine assuming there have been no modifications to the gasket when you put a bolt through the intake, and through the gasket, into the head, that will line the gasket up to the head perfectly (within head/gasket machining tollerances).

I think I'll do that but it leaves concern for the actuall clamping force from the intake to the head, hopefully this doesn't leave anyh gaps anywhere for coolant/oil leaks.