CMG, mine came with studs. Mine also had the 3" spacers between the manifold and the riser which I think were standard in order for the exhaust to exit correctly for the silent thunder platform. Bill, I don't know your particular setup with the 7.4s but I had to purchase one new riser spacer (OEM Mercruiser part) shortly after I purchased my 311 and the kit came with studs and nuts. It would be very hard to get an accurate torque reading on a bolt that long. Maybe there were different set ups on the Mag and the 7.4. I know the more recent stainless risers used bolts also but the bolts were short because the bolt bosses were cast at the bottom of the riser rather than going all the way through to the top.

Bill - thats the same set up I saw just last week on a 272 that had big blocks, but the 311 needs the additional 3" spacer like Croozin said so you don't typically see it in a Merc diagram.
Croozin, am I right that you have 7.4's and not mags?

I figure someone must still have stock set up on a 89 311 w/mags and can confirm.

Might be different on a 311, but my '89 292 (365 Mags) had Threaded rods and not bolts as shown in your picture.

I know this as I switched to Stainless Marine 2 years ago...........went down to the shop just now to look at the risers/threaded rods. The latter are 7 inches long to accomodate the oil filter bracket, with the rest 6 inches.

Hopes this helps.

Looks like the risers have been off at some point on your pictured engine.

I think 311's engines sit a little deeper in the boat, mine are 10 1/2 on the filter side and 9 1/2 on the others

I had Mags in mine but I changed over to EMI Thunders when I did the rebuilds in '03. Mercruiser has some really innovative ideas on some things but the old cast iron manifolds/risers with water flowing in between are so antiquated. It's just a water ingestion problem waiting to happen (which is the major reason I went with the EMI plus dropped about 50 pounds per manifold!). By the time you see a external water leak you've had an internal leak for some time and the damage is done.

Not going into the water this year. A work in progress

Where did you get the picture of Audiofn's boat??

Audiofn's looks as hopeless as mine?

Audio's will be petrified before it's done.

HEY THERE IS ANOTHER ONE AS DUMB AS I AM!!!!! MY mom said that they broke the mold.... I always believed her but LOOK THIS IS PROOF!!!!