I cant seem to get a consistent answer. I am installing new ex- manifold on a 70 SS 396. I ordered the correct bolts from Ground up. The old set had a little black washer then a lock washer. I put the little black washer on (and the french washers) just does not look correct? The bolt heads are flat. Do I even need the washers?:confused:

my car has never had the bolts out .Take a look at my sig. and think there a pic of the manifolds.

The correct exhaust manifold bolts for a 1970 B.B. have no flat washers or lock washers of ANY type. 1970 Big Blocks have 8-- 3/8' Hex head bolts for Cyls. 3-5- 4-6. Cyls. 1-7-2-8 Get a mushroom type bolt or you may say it has a built in flat washer on it, The four corners of ALL big blocks in 70 have this style bolt on cyl. 1-7 & 2-8
The threads on the eight bolts that " LOC " down the four corners have a binding type thread, To make this simple, All bolts have a peak & valley on the threads. The eight lock bolts for the corners have NO valley. The correct loc bolts have a peak on the thread, half way to the bottom the die leaves the thread with a FLAT and NO valley.
When this " Correct " loc bolt is screwed into the Cyl. it will be BINDING as it goes into the hole, Feels like you have it cross threaded. This was a cheep way to lock the four corners down on 1970 Big Blocks
Here are the Specs. for the eight bolts that loc down cyls. 1-7-2-8. O.A.L. is 1 9/16' Under the head to bottom of thread 1 3/16"
Outside Dia. "flat washer area" is 11/16"
Head markings---a 3/16" circle in the center of the head and 6--1/8" lines from the center circle pointing to each peak of the bolt.
If you look at a unmolested 1970 big block, It will have 8 standard 3/8" bolts on the center four clys. and 8 loc. bolts on the four corners. If you use any type of a spring pressure loc washer, The heating and cooling cycle MAY cause the loc washer to loose its tension and your manifold may or maynot become loose. This all may sound like a lot of B-ll Ship, What you have just read is fact, not fiction.
Bob:thumbsup:
These bolts are on my LS-5 M-22 El Camino that I ordered in Feb. of 1970 at Sahli Chevrolet in Beaver Falls , Pa.
The road to perfection is always under construction.......

Bob, I checked all the bolts from Ground-up. The do not have any valleys. I have installed the drivers side manifold but did not tourk it so I will take the lock washers off and replace the bolts. I did install the french locks on both ends. I see you did not mention the french locks? Does this big block need them?

French Locks were not used. (a parts Catalog myth)

Nor were the spark plug heat shields (another mythical catalog selection item)

Nor was there any type of manifold gasket used.

I agree with the man from "Florence Y-AL" ( on the water tower).
Also , If the 70 was a Fac. A/C car. The SS cars had little CHROME brackets ( non SS cars they were painted orange) that attached to the valve covers for the spark plug wires.
Wires 1--3--and 5 were attached to these brackets, And not to the valve covers. WHY ??? Wires were routed under the A/C compressor and not between the valve cover and the A/C Comp.
If you need more useless information, Just ask...............
Bob:thumbsup:

Now I have to see. I know the rear wire holders are chrome. This is confusing LOL

Bob,

Where do you buy the correct bolts?

I do not believe anyone sells the correct " 8 " corner bolts. BUT if you want to get real close--- Intake manifold bolts from paragon. They look real close to the correct stock lock bolts, I do not believe anyone could tell the difference, May have to shorten them---Not sure.
Get a correct " ORG "intake manifold bolt and screw it in or check the length by checking the depth of the bolt hole.
I have 16 org. lock bolts. Not in a hurry to get rid of them.
70 intake, LS-5 or any IRON style manifold bolts are a close match.
Org. intake bolts have an " O " in the center. I Think?
Bob

Thanks for the info Bob.

GM stills sells the exhaust manifold bolts. Outboard or locking thread shouldered type GM # 3909821. Inboard bolts non-shouldered # 3736035 not exactly cheap but still available from GM.
Chris

French Locks were not used. (a parts Catalog myth)

Nor were the spark plug heat shields (another mythical catalog selection item)

Nor was there any type of manifold gasket used.
X2:yes:

I agree with the man from "Florence Y-AL" ( on the water tower).
Also , If the 70 was a Fac. A/C car. The SS cars had little CHROME brackets ( non SS cars they were painted orange) that attached to the valve covers for the spark plug wires.
Wires 1--3--and 5 were attached to these brackets, And not to the valve covers. WHY ??? Wires were routed under the A/C compressor and not between the valve cover and the A/C Comp.
If you need more useless information, Just ask...............
Bob:thumbsup:
Good one Bob LMAO:D

GM stills sells the exhaust manifold bolts. Outboard or locking thread shouldered type GM # 3909821. Inboard bolts non-shouldered # 3736035 not exactly cheap but still available from GM.
Chris

Thanks Chris.

I am getting to many differant facts. The book shows french locks I put them on now you say no french locks....Help

no french locks.

I am getting to many differant facts. The book shows french locks I put them on now you say no french locks....Help

What book are you referring to?

The aftermarket parts catalog?

There are scores of parts for sale in these catalogs referancing years used that are incorrect. Good for sales, bad for correct restorations. Just off the top of my head for 1970 parts.

1. French Locks, never used.
2. Spark Plug heat shields, never used.
3. Spare Tire cover, never used. (I got fooled by that one myself early on, and have an extra if you want it :) )
4. Plastic Cowl screens, never used.
5. Radiator warning label, never used.
6. Blue GM Door sticker. never used.

And countless others I'm sure.

The purpose of the aftermarket parts catalog is to sell parts, as apposed to being a referance guide for correct restorations.