Head miss aligns to bore, valve tries to open and hits bore edge stopping its travel. Rocker breaks, rocker stud bends or pulls out often cracking its casting boss in the process, pushrod buckles, valve gets bent are some of the next options.

Bogie

 

Dowel pins are used when components are required to be in perfect alignment. I am not sure on which ones you may need in that particular situation.

Sam

 

I don't know that one dowel pin locator is much better than another. I've always just gone to a local parts house and got generic, or whatever they had. Only time I ever had an issue was on my present BBC, and the dowell pins didn't want to go into the Edelbrock heads I have, when test fitted. I had to use a blade to slightly chamfer the head hole, so it would then drop over the pin snugly.

 

Any generic dowel pin should work, you can get offset ones too if you need to correct manifold alignment.

 

Correct me if I'm wrong but aren't the dowels used to align the head with the block? I would want the heads aligned with the block properly and then work on any manifold alignment issues by reworking the manifold, not mis-aligning the heads to the block to align the head and manifold. Just asking.

 

Ok, sounds unanimous. It's a gm 350/290 crate that's getting vortecs. I suppose I will search by motor type on Summits site and go from there.

Isn't it 4 pins per head?

 

2 per deck 4 per block and they are needed !!!!!!!!!!!

 

Mr. Gasket 4375 or Pioneer S-1110 dowel pins. Size: .310: OD x .562" long. One pair for each head.