Just as title states. Is it 52mm or can you machine a 58mm TB from stock casting?

Brandon

 

Vendors that offer 52s though 58s usually can machine a 48 into a 52, but use new castings for 54s, 58s etc.

 

So your saying somewhere around 52mm is the largest you can machine the stock casting right?

Brandon

 

I had a 52 one, and that had touches of holes in the backside of it. I have seen some places on ebay go to 53, and 53.5, but i would assume you would need a perfectly centered TB to start with, and some very precise machining. Either that, or go back over it with epoxy and fill in the holes.

 

I've bored alot of LT1 throttle bodies and the largest you can go safely is 52mm. Yes you can get 53 or 53.5 but you have a very good chance of breaking through a casting wall. I did one for a friend of mine that had a TPI and wanted me to see how big I could go. Almost to 54mm and I broke though a wall. Also any larger than 52mm and you will have to port the bores in the LT1 intake.

Even on some stock castings that are bored to 52mm will have the screw holes exposed, which will not hurt anything. The screws will seal the holes.

 

Cool. 52 it is then.

Brandon