65-74 Big Block Exhaust Manifold Bolts
 

1 set of 16 A Big Block Exhaust manifold bolts for 65-70 cars. These are the non locking thread. VERY HARD TO FIND UNRUSTED ORIGINALS. 350.00 shipped to the lower 48 I have a few more sets of F, C and O.

Re: 65-70 Big Block Exhaust Manifold Bolts
 

Good looking clean set.
Are they all the exact same length and are any of them shouldered?

Re: 65-70 Big Block Exhaust Manifold Bolts
 

Rick, This set is all the same length and not shouldered. I have shouldered locking exhaust manifold bolts I will be posting. Depending on options...P/S....A/C...the # of bolts required vary per vehicle. Shouldered locking thread bolts started in for some models in late 67 on Corvettes with AIR for the outer 4 ports I have seen some Camaros Chevelles and Novas with shouldered and non shouldered. Here is a picture of a set of mixed hex and shouldered bolts. I'll post more tomorrow.

Re: 65-70 Big Block Exhaust Manifold Bolts
 

Yes, both types like these, very common on Tonwanda motors.

https://www.yenko.net/ubbthreads/pics...3-dscf9609.jpg

Re: 65-70 Big Block Exhaust Manifold Bolts
 

Mike,

Looks like a very nice 1970 SS396 Chevelle :-)

Dan

Re: 65-70 Big Block Exhaust Manifold Bolts
 

70 396? I wouldn't think an L78 Chevelle would use that LH smog tube. [img]<<GRAEMLIN_URL>>/no.gif[/img] LS6 yes..........that style smog tube starts showing up on Chevelles sometime in January, too late for an L78 Chevelle. Ok Mike who's motor is it? BTW nice hardware you've been offering up Rich!
Chris

Re: 65-70 Big Block Exhaust Manifold Bolts
 

Chris
It is just a ref: shot I took somewhere to show off the OE bolt layout, and thanks for keeping Dan stright... [img]<<GRAEMLIN_URL>>/naughty.gif[/img]

Mike

Re: 65-70 Big Block Exhaust Manifold Bolts
 

Yes.
Just like Mikes photo above,most big blocks,including trucks,came with a longer shouldered bolt on the 2 outside exhaust ports...(bolt #3909830 3/8 X 16 X 2&amp;1/16).
And a shorter,non-shouldered and non-washered bolt on the 2 inside ports...(bolt #3909821 3/8 X 16 X 1&amp;3/16).
Also remember that what GM recommended an engine assembler to install vs. what that assembler actually did install,were not always the same thing.

This is one glaring detail that so many restorers/owners overlook.

Re: 65-70 Big Block Exhaust Manifold Bolts
 

Mike great Picture and the confirms what I have observed on many cars the outer ports got the flanged head locking bolts while the inner ports got the non locking thread non flanged bolts!!!

Re: 65-70 Big Block Exhaust Manifold Bolts
 

I have a couple engines photos and yes both sides are the same. I have seen some other good survivors and did not have the camera. Keep your eyes open when you run across those not messed with cars [img]<<GRAEMLIN_URL>>/biggthumpup.gif[/img]
The dip stick tube fits better too with the non shouldered bolt.

Mike