bbc blown alcohol bore size question

i have a bowtie block that hasbeen filled completely to the deck and o ringed,my question is about the bore size its at 4.625 will that cause any issue with the bore so large? cracking or ? engine is a tall deck with a 3.750 stroke and long aluminum rods,8-71 hh littlefield bird catcher etc.

 

The block is fine. Only issue will be keeping it sealed between combustion chambers. It's oringed so that's good but there is very little material on either side of the oring for the gasket to lay down on. I had almost same set up and boost to 24 lbs was fine. gl

 

I have run a couple of tall deck Bowtie blocks and it seems that they tend to crack between the bore and the head bolt hole--number 8 cylinder on one and number 2 cylinder on the other. One block was filled to the top, the other was not. Bore size was 4.530 on one and 4.475 on the other. Both oringed and 14-71 blowers. Just my experience. Still running the unfilled one. JW

 

Also consider the added piston weight on the small end with a short stroke that it will be trying to sling around. ..????

 

rod is 7 inches long and the compression hieght will be around 1.325

 

Does your block have the figure eight style o-rings are they four seperate o-rings on each side? If seperate, what is the OD of the o-ring. Standard BB Chevy is normally 4.800.

 

kinda looks like a real tight 8

 

Make sure all the o-rings are in good shape. If not, replace them. Have a machine shop cut a reciever groove on the heads to match the block. Around .010 to .012 deep and .010 larger than the o-ring material. Use a gasket thickness of .062 are less. Loosen and retorque each stud, one at a time, in order after the first outing. Should work fine.

 

thanks for the info.i will give it a try