ZD75blue

Hey all the continuing saga of exhaust system/emmissions restoration is up hill

I am wondering what size the exhaust manifold bolt is? I thought it was 9/16 (craftsman) but tried a 14mm (which fit better :confused: ) so I'm wondering is the bolt a 17/32? Thats the best I can figure but I dont have one in my set.

Is there a bolt size chart anywhere thats got all the different parts and stuff?

Thanks

A very :confused: very :mad ZD

PatsLs1vette

they are 9/16 but sometimes over time they rust and get smaller..

killain

all 1978 and later Chevrolets were built using both SAE and metric bolts. so it very well might be a 14mm or a 9/16, however a 17/32 is not a standard automotive fastener, so i would bet it's a 14mm. Good Luck. :bb

theandies

Before I converted over to heddars I went to my local :chevy dealer and got the correct bolts for "Ram Horn" manifolds. I dont know the size of the head and also don't know the year :chevy changed over to metric. I'll go out and measure them for you.
John

ZD75blue

sorry its a 75 :bb

been waiting for an excuse to use :bb but hate it when its for the serius stuff

I cant get over why you would change to use metric too on the same car but hey who knows (i would think that they had a large supply for metric bolts cheaper than standard and the just changed over, "gm" says "bean counters" in two letters)

ZD

mrvette

AFAIK, the thred taps on all chebby SB's are the same, for all accessories...
3/8-16 is the tap on accessories, intake and exhaust.... not the cap size can be whatever, as the changeover was slow and painful...so majority of time a 3/8 16 bolt has a 9/16 cap on it...using a metric size is a favorite old tyme trick for rusted bolts, where car has been reduced....I ony use 6 point sockets, those damn 12 point garbage SEARS loves to sell on sale pushes...are just bolt wringers...nothing more...garbage...

as the years went on though, say by C4 vintage, the caps were all metric, but the bolts were still 3/8-16 american tap....go figger...
I guess the foundry taps are too expensive and must be hard as a teenage dick...
considering the amount of production they do through...

GENE

GENE

ZD75blue

hey gene thanks

I already rounded off a bolt with the 12 point I'm just going to break down and buy 6 point box wrenches and sockets in all sizes and put the rest up for sale on ebay :yesnod:

ZD

PRNDL

You just reminded me that I forgot to stop by Paragon at Carlisle last week. Last YEAR I got a poster from them that has pictures of all kinds of bolt heads with sizes and function listed. Pretty neat poster. MJ