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Need more bolt sizes

Stage8.com makes some of if not the best hardware for stopping things from backing out. However GM hit a homerun with the factory manifold bolts on this engine. Imo justRun factory bolts here. Yes they are trilobe and it works amazingly well. That also makes removing them easier few years down the road after rust and heat cycles because it works kinda like a self tapping bit that removes rust as comes free.
 
@SnowDrift heads up too that the bolt holes for securing the transmission to the engine are metric, M10x 1.5 on the GEP block. The early 6.5 blocks like yours most likely have 3/8- 16 threads, my '95 141 block did.

I just thought of this as I'm putting a GEP block in a '93 and the bellhousing studs most likely won't work either.

So, anyone know of a source/ part number for the metric studs? Plain bolts won't work in all locations as the starter heat shield mounts to one of the bellhousing studs. And on a manual the clutch line is also secured to a stud as it snakes behind the engine
 
DieselAmateur said:
@SnowDrift heads up too that the bolt holes for securing the transmission to the engine are metric, M10x 1.5 on the GEP block. The early 6.5 blocks like yours most likely have 3/8- 16 threads, my '95 141 block did.

I just thought of this as I'm putting a GEP block in a '93 and the bellhousing studs most likely won't work either.

So, anyone know of a source/ part number for the metric studs? Plain bolts won't work in all locations as the starter heat shield mounts to one of the bellhousing studs. And on a manual the clutch line is also secured to a stud as it snakes behind the engine
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Thank you. Yes, I had discovered that on the bell housing bolts.
 
denata said:
Nop.
15552852
One side 3/8"-16X1.38 and other side M8X1.25X20
View attachment 84976
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What years were 3/8" and which were M10x1.5?

I have some of both here. Or at least I did until yesterday.

I used one to attach the grounds to the frame by the starter. The M8 hole was stripped, so I tapped it to 3/8-16 and attached the grounds to the M8 end. I did another with a M10 stud previously.

I torqued the 3/8-16 to 15' lbs & the M8 x 1.25 to 11'lbs
 
SnowDrift said:
To clarify @denata , my block is no longer the original '95 which was SAE threads. The block I have now is metric threaded. M10x1.5 are the threads for the bell housing to transmission. I'm just not sure what the length is to be.
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I am guessing the bolts are the same length as the 10 mm part of the studs.

These are bolts out of my 10mm can.

The 15mm part of the stud measures 34mm. The bolt next to it measures the same.

Above is the 3/8" starter bolt with washer head. I'm guessing it was off the 1989.

I also have at least one washer head starter bolt that's M10x1.5
 

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I believe I need 3 studs and 3 bolts, after looking at it tonight. Two in the driver side should hold the bracket for the fuel lines and one on the passenger side for the heat shield. On the heat shield, I'm wondering if there was a design change that eliminates the need for the small steel bracket. If so, then it makes sense. If I have the wrong heat shield, then that could explain some things too.

The original is shown below next to what I bought for a replacement.
20231203_151110.jpg

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20231203_151025.jpg
 
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