I'm putting together a rebuilt Chevy Small-Block engine and automatic trans and neither came with the bolts to connect them and installt them so I need the bolt sizes so I can go to my well-stocked hardware store and get them. I tried the local Auto Parts stores but you know how much help they can be "Bring in an example and I can try and match one up"- I think "Hey DUMBASS- if I had an example why would I be calling you???" Anyway, here's what I need size, thread pitch and quantity for (I'm sure others will benefit from this list)- Transmission to engine block? Motormounts to engine block? (sidemount style) Long motormount bolts that go through a small-block motormount? Also, the flywheel bolts are specific hardened bolt with a shorter head, correct? Or is there a harware store equivilent that would work?
3/8" -16 x 1.25" for the Tranny Bell (6) 3/8" -16 x .75" for the Side Motormounts (6) - Probably should use a lock washer on those too (I could be wrong on those lengths - but that is about the lengths that I usually use for them) which style motor mount are you using? - early style or late style (clam shell) - there is a big differance in length. Early style I think is around 4" or 3.75" - somone else might know better I don't have 1 in front of me Flywheel bolts are specific - you can pick up ARP's @ a speed shop or a machine shop should be able to get them for you next day. Manual Flywheel bolts are a bit longer than Auto Flexplate Bolts.
If it were me, I would go to a junkyard and get some.......The crap that the hardware stores have these days, is just that....CRAP
Further... if its a 1-piece rear seal block, the bolt pattern is smaller on the crank for the flexplate. The ARP standard bolts will not fit, because the heads hit the crank. You need the specific bolts for the 1-piece rear seal. *(not sure what you have , but figure let you know, just in case. nothing worse that getting under there and finding you have the wrong stuff)
Forgive my lack of knowledge- does this pertain to early or late engines? I have one 1962 small-block and one late model- both going together now and both need flexplate bolts. Thanks for the info!!!
Awesome info! Thanks!!! My hardware store has grade 8 stuff that seems good, that should be fine, right?
yep, def use arp or dorman grade8 for flywheel and torque converter, should be available at all chain part stores.
Yeh should be ok - USA (or quality) made grade 5 should be fine too - for the motor mounts and bell. Pre '85 blocks are all 2 piece rear main seals. 1pc and 2pc have the same thread size - but the bolt head is different Torque converter bolts are very short - if you have a converter that they thread into they are proably 3/8-16 x.75" or .50" Same if they are "nut and bolt" It is also posible that the converter bolts are metric depending on what year the tranny is - double check that before stipping the threads on a converter that is threaded
I second the junkyard recommendation, the bolts for that stuff all seem to be in 1/8" increments on lenght, the hardware store will have bolts that are too short, and bolts that are too long, but none that are just right. And the quality....
One of the nice parts about being old . lotta left over factory hardware laying around ,as in drawers full ..
Since you don't have flywheel bolts, go on Ebay and order some ARP bolts for a Chevy. Its waaayyyy too much work to go to a junkyard and pull a transmission to get all the bolts you need. You will pay more for the ARP but they will never break or let you down. The last thing you want is small head hardware store bolts holding your flexplate to the crank.....and they are low grade bolts. The flexplate bolts will be fine thread. You also need bolts for the torque converter. As for bolting the trans to the block you don't need the ARP. Try looking for some flange head serated bolts on Ebay. Buy them in bulk so you have some extras. Try this guy, I've had good luck with him. If you buy in bulk, you have some for other things and you can always cut them off if you need shorter ones. https://www.ebay.com/itm/50-3-8-16x...346909?hash=item3cd6a79ddd:g:YfgAAOxy14VRSbtm You can find all these on Ebay and not waste time and money driving all over town and not finding what you need. While you are at it, you will need special bolts for your starter and probably some shims.Then you have to know how much space to set the starter gear to the flexplate. Anyone have that info handy......
Oh well.......No Harm, No Foul . Maybe in the future there will be someone who needs this same info ............
I have owned an aftermarket flex plate that was thicker than stock. Might be the trick piece for those one piece main seal engines (that I have never owned). Another trick to remember is to use a couple of extra length 3/8" bolts with the heads cut off as an aid to slide the transmission into place. You will think you have three hands and even happier not to have purple finger nails.
Naw he is still wondering what to use and probably how many inch-pounds if torque and what the metric equivalent of that is incase he ever drives to France. I wonder if this is the thread that got him banned. LOL
I believe he is in Delaware and owns a business....body shop/painting/restorations....I always enjoyed talking to him when I saw him at shows.....
As I live in the Twilight Zone, whatever time the poster lives in doesn't matter. Eventually, someone will read my comment in their own time zone and if it applies to them, well that's what Rod Serling used to call 'a happy coincidence.' Blessed be he who has faith in the reciprocity of information, for he will harvest his information from the libraries of the mind.
I laugh every time I see a post asking what length bolt is needed...... Do these guys not own or know how to read a tape measure or ruler or yard stick?
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