# Offset Dowel Pins and Bellhousing Alignment



## jtwoods4 (Dec 22, 2011)

Tongiht I was installing my lakewood bellhousing on my 400. While installing I was thinking about the numerous articles I have read about "offset" dowel pins you can install in the block to better align the bellhousing.

Well.... The bellhousing has about 5 bolts that go directly into the block. Since the bellhousing bolts to the block how would an "offset" dowel pin make any difference. The bellhousing is only going on the block one way, where the bolt holes line up and the bolts go in. If the dowel pins are out of whack then the bellhousing holes are not going to line up with the block bolt holes.

I dont see how Dowel pins have anything to do with alignmnet. Ultimately the bellhousing is going to align to the bolts in the block.

Does anyone disagree?


----------



## ALKYGTO (Mar 29, 2010)

I do! 

The bolt holes are only slightly larger than the bolt diameter but when doing an alignment thousandths count. Did you indicate the bellhousing in? Usually they are very close but a misalignment could spell trouble with clutch engagement and bearing wear and noise. It's just good practice to make sure it is aligned.


----------



## jtwoods4 (Dec 22, 2011)

Well I don't have a dial indicator. I'm just going to bolt on the. bell housing and hope it works out. With 600 foot pounds of torque I should know pretty quickly. Hopefully it'll work out okay, I would rather punch myself in the face repeatedly than take everything apart again.


----------



## ALKYGTO (Mar 29, 2010)

I found this - http://www.hurst-drivelines.com/files/GM Dial Indicating - RobbMC instructions Revised 6-15-09A.pdf

and it pretty much says that if you are using an OEM bell housing and your engine hasn't been line bored bell housing alignment checking isn't necessary. I would also say that the quality of aftermarket Made in USA bell housings are going to be quite good and they say the tolerance is +/- .005 on alignment.


Chances are you'll be fine :cheers.


----------



## jtwoods4 (Dec 22, 2011)

Thanks for the link. I hope it works out. The stock Dowel pins fit fine with the bellhousing backing plate but by the time I put the bellhousing on they were barely long enough for the bellhousing to sit on. Longer dowel pins are probably needed. Arrrrg, at this point I am just ready to get the car back together. I had the same bellhousing on a 455 engine in the same car and the dowel pins were longer but not offset. Everything worked great with the other engine. The new engine with the shorter stock dowel pins has me really concerned though. I dont think I can do anything about it now since the engine is in the car. 

What could happend it the bellhousing is out of alignment?


----------



## ALKYGTO (Mar 29, 2010)

Difficulty shifting, premature bearing wear, worst case damage to trans. Read the link I sent you and that'll give you a better perspective on it.

Honestly the pins are just there to position the bellhousing so even if a little bit of them is in the holes should be fine. Is there any way you can move the pins out towards the back of the block (hammer and punch or air hammer)? I had the same dellema when I installed my block saver too but enough protruded through to position the BH. The bolts hold the bellhousing on so you'll be fine I'm sure.


----------



## jtwoods4 (Dec 22, 2011)

Thanks ALKYGTO. Building these cars can get stressful sometimes.


----------



## ALKYGTO (Mar 29, 2010)

Oh Yeah, but that all goes away when you mat the gas and paint the street black. arty:


----------

