The Stovebolt Site Forums The Shop Area Engine Shop Chevy 250 intake exhaust question

Using a standard exhaust manifold can I cap off the area that connects to the intake and then use my Clifford 2 barrel intake?

I’m answering my own question, I assume so, I’m ordering the manifold!

Since I’m on the exhaust thread, are there exhaust intake mounting hardware available for the 250? I don’t know its name but they hold the manifolds down with a bolt. I think you can see it in the picture.

Remind us what year the engine is from?

Chevy IL 6, 250.

There are differences for different years. What *year* is it from?

Sorry, 1976. It has 2 studs & 4 bolts I believe. At each end is a smooth stud with no threads.

>>are there exhaust intake mounting hardware available for the 250? I don’t know its name but they hold the manifolds down with a bolt.<<

What do you mean by "hold the manifolds down" ?
I don't really know if the Clifford can be used over the stock cast exhaust, with clearance for a block-off plate. I originally ran tube headers under the stock intake. You said you ordered a manifold, so you'll find out. The block-off plate is going to have to be fairly thick and use a good gasket.

You are showing tube headers in your picture. Why are you not using them?

>>It has 2 studs & 4 bolts I believe. At each end is a smooth stud<<

Most heads have lost the two threaded studs over the last 50 years. I think most head rebuilders remove them and never re-install.
The locater studs on each end, are threaded into the heads and are easily removed with a little penetrating oil.
When using tube headers, it is best to replace the locator pins and the 4 bolts with threaded studs, for a total of eight threaded studs along the length of the head for better sealing. A tube header gasket such as this should be used . https://www.summitracing.com/parts/rra-18-2830-1
I'm guessing here that the reason for a stock manifold is exhaust leaks.

You ask
>>are there exhaust intake mounting hardware available for the 250? <<

For stock mounting hardware, you'll have to scour wreaking yards. I used 6 of the short original type straps. The intake and header flanges have different thicknesses so I ground a little on one side to make them sit properly under the stud nuts. Both end studs just use a flat washer and nut.

You really should listen to those guys about fixing those engine/trans mounts.
In the picture, the manifolds are just sitting in place, without any fasteners. Just the 8 studs.

I just now expanded the picture of your engine posted above. I remember reading about your headers a couple of weeks ago.
That explains why you are removing the tube headers. I had made the assumption that it was because of header gasket leaks.
I would think a good muffler shop would have the skills to replace that bad section and reroute that tube with the needed clearances.

The guy that built your truck was a real hacker. good luck.

Richard, you figured a lot correctly. No one in my area would or could bend the small diameter header pipes.
Yes I have the exhaust manifold and made a 1/4 inch plate with the gaskets that came with it. I’ve not set both intake & exhaust on the block yet, so that was my concern. If it does not fit I guess I’ll have to get a regular intake for it.
Seems odd that the end studs (locater pins) didn’t have threads, since they do come out I will do that & replace with studs or bolts.
I’ve found no one that knows how to fix the motor mount issue but I just contacted a local company that’s been doing old vehicles for years. I’ll be moving forward with them.
I appreciate your input!

The two studs on the outer edge should not be bolted or held in place with nuts.

They are specifically designed to allow expansion of the manifold.

This! If you bolt them tight, you will crack the manifold from thermal cycling.

X3 on the locator pins for the cast manifold.

>>No one in my area would or could bend the small diameter header pipes.<<

If I were repairing that header, I would find an old section of exhaust pipe or an old busted up header and cut a piece out that has a suitable bend(s). I have MIG, TIG and Gas, but no pipe bender.

Google map shows a dozen Welding Supplies in the Darlington area. Surely someone in one of those shops would know someone that could do a small header repair.

There's no rocket science to custom building motor mounts, buy a set of 250 motor mounts from your local FLAPS for the year of the engine. Bolt them to the block, hang the engine and transmission together where you want them to live and weld plate steel from the frame to the new motor mounts. Them mock up the trans crossmember, bolt it in place and you're done...do a little research on engine angles to make sure you don't end up with driveshaft vibrations.

Mike B