dath

I'm posted a few questions in a single post a couple days ago and just remembered that I never really did get an adequate answer to a question about my new torque converter bolts... I got a set of ARP converter bolts (Summit # ARP-230-7303) and a Summit 400 flexplate (Summit # SUM-G101SFI) and noticed that the bolts do not fit through the holes in the flexplate. The bolts are 7/16" thick, as are all of the bolts that Summit specs for a TH400. They also do not fit through my old flexplate, so I'm pretty sure it isn't just the flexplate at fault. I called both ARP and Summit about it and ARP wasn't much help, they said they have bolts in 3/8" and 7/16", but their application guide specifies 7/16" for my application. Summit said that I should just ream the holes in the flexplate a bit.

Any suggestions on what I should do? I read somewhere that the torque converter bolts should not fit tightly and there should be at least 1/32" clearance to prevent the bolts from causing excessive runout in the flexplate. Should I just fall back to a Grade 8 3/8" bolt? I did notice that my old flexplate bolts were smaller (probably 3/8")...

gkull

Very common to drill when using aftermarket better convertors. The hole should be larger than the bolt threads to help prevent stress cracks. The bolts star type washer uses compression to hold a greater area of the flex plate.

dath

Cool, think I'll just make the holes a bit larger then. I wish the parts houses had better tech people that could just tell me that. Summit thought they maybe just didn't drill them large enough in the first place... :rolleyes:

gkull

If you buy SFI rated Flex plates they are made for the bigger bolts.

Since I race I have to run all SFI parts. I also believe in safety.

dath

Interesting... It is an SFI flexplate, has the sticker and serial number and everything... I agree with safety, that's why I was concerned about this...