69 BB intake bolts

[Brad S.]

I have two differant styles of intake bolts for my 69 L-36. The first has an A head mark , flanged washer head and a flat head at the A marking. The second is a M head mark , flanged washer head and a recessed head at the M marking. Which is correct ? Thanks Brad

[Jack H.]

Re: 69 BB intake bolts

They may BOTH be correct! I've seen quite a few 'untouched' engines where fasteners on the RH side were from one source and those on the LH side were from another source.

That suggests there were RH and LH workers on the assy line installing items as the engine came by and their supply bin(s) of fasteners were refreshed 'asynchronously'...

[Grant W.]

Re: 69 BB intake bolts

Hi Brad
From what I have seen on 2 original 68 cars.
A flat head flanged washer was on the 435hp and L88's
M recessed head with flanged washer was on the 400hp and 390 hp.
The 69's were also similar application.
Thanks, grant

[Joe L.]

Re: 69 BB intake bolts

I have two differant styles of intake bolts for my 69 L-36. The first has an A head mark , flanged washer head and a flat head at the A marking. The second is a M head mark , flanged washer head and a recessed head at the M marking. Which is correct ? Thanks Brad

Brad-----


For 1968-74 big blocks, there were 2 different length bolts used for the intake manifold. The 2 bolts used at the intake bolt positions that also retained the left front lift bracket were 1/8" longer than the 14 bolts used at the other positions. Very often, if not always, the different length bolts will have different headmarks since, at any given time, different manufacturers may have been supplying the different length bolts. It's also very possible that over the years of the car's life, the manifold was removed and the slightly longer bolts installed in some other position than they were originally. So, where you found them might not be the forward 2 left side bolt positions.

Another thing: "A" and "M" were VERY common headmarkings for intake manifold bolts for big blocks. However, "A" and "M" flanged head bolts are VERY, VERY UNCOMMON hardware store or automotive repair shop "bin" replacement bolts. So, it's very unlikely that such replacement bolts would have found their way onto the car over the years.

If you find that there are TWO bolts with the different head configuration and headmarking and FOURTEEN with the other configuration and headmarking, what I described above is likely the reason. If you have some other combination of head configuration and marking, then it's likely that the situation that Jack described is what occurred. In either event, with the bolts all of "A" and "M" headmarking, I think they're very likely original to the car.

[Brandon T.]

Re: 69 BB intake bolts

not sure if 68's was the same but on my 68 l36 the original bolts were headmarked FP.....

[Joe L.]

Re: 69 BB intake bolts

not sure if 68's were the same but on my 68 l36 the original bolts were headmarked FP.....

Brandon-----


"FP" is yet another semi-common headmarking seen on big block intake manifold bolts.