1999 454 7.4 Vortec Upper Intake Manifold

I have acquired this engine on a P30 chassis (motorhome) and the previous owner seem to have cracked the upper intake manifold right at the EGR valve hose connection (see pictures). There was a bathroom corrugated hose in its place capped at the end, no idea why but the hose was barely there and when I wiggles it its came off leaving that hole in the Intake manifold connection. I haven't removed the sensor yet to see if its capped off or if its still operational?

I was going to get a new manifold and run the EGR line to the exhaust manifold again and get it back to stock. But aside from used units on eBay I cant seem to find a direct replacement for that intake manifold from any manufacturer. It's as if that particular model never existed. If I look up a replacement anywhere it gives me all kinds of different options that don't seem to fit all the ports and placements of the current manifold. If someone could shed some light into that for I would greatly appreciate it.

The upper intake manifold is not a wear part and doesn't fail often. You won't find an aftermarket replacement. It's probably discontinued from GM, and you will need to either have your original welded and remachined, or find a used one. A used part will likley be your best option.

The EGR hose is NLA from GM, and is also unavailable from the aftermarket. The prices I see for those on ebay are ridiculously high. I have no idea how to fix that cheaply.

What sensor are you speaking of?

Thanks for the info. I meant the "valve" when I said sensor. I dont know if that EGR valve is still operational since they messed with it and the hose was not original and was capped at the end. I can see tons of 454 Upper Intake manifolds for sale at various sites, just not that one. I dont know if its a real problem yet since they put a bunch of sealant around it but I am researching a way to replace it (I am replacing the exhaust manifold which is leaking pretty bad first). Just wondering why I don't see this particular one for sale, but I see several other types. Just seems odd.

wmoura said:

Thanks for the info. I meant the "valve" when I said sensor. I dont know if that EGR valve is still operational since they messed with it and the hose was not original and was capped at the end. I can see tons of 454 Upper Intake manifolds for sale at various sites, just not that one. I dont know if its a real problem yet since they put a bunch of sealant around it but I am researching a way to replace it (I am replacing the exhaust manifold which is leaking pretty bad first). Just wondering why I don't see this particular one for sale, but I see several other types. Just seems odd.

Click to expand...

That hose looks original to me.... well what's left of it.

There are very few intakes for a big block chevy that consist of an upper and lower.... if your seeing an upper intake for a 454, it's mostly likely the stock part that you have. It's the most common.

To echo what 454cid said, the fitting that's still on your manifold is original. This


looks to be a direct replacement for your damaged manifold. I have no knowledge of the listing - I just did a search for visual and pricing reference. Would be a good idea to get the seller to confirm the condition before buying.

It's probably 50/50 on cost just replacing what you have vs. finding someone to weld and then machine your damaged one. If time/effort is factored it, the ebay route wins. One benefit of welding and machining is that you could have it tapped to something standard and convenient. I once knew what those threads were and I seem to recall they were not common. As mentioned, that EGR pipe is not available new from anyone at any price. If you replace the upper manifold, you'll need the upper intake manifold gasket. The GM one is superior to Fel-Pro's offering. It has the locator pins stamped into it unlike the plastic donuts Fel-Pro uses that have an unfortunate tendency to jump into the lower intake.

I can verify in a bit, but that sure looks just like the normal Vortec 454 intake. I just yarded one out of a 99 Suburban so I have it handy out in the shop. I’m not aware of any upper intake differences aside from marine specific ones.

Edit: Looking closer, is the manifold actually cracked, or just covered in JB Weld? It looks to me like they just couldn’t get the fitting off from the old hose.

So here is my 1999 Suburban 454 upper intake. The only difference I seem to be able to tell is that your throttle body might sit slightly further out, but that might just be camera angles. All other ports look like they are identical and present.

Wow, thanks for the pictures, that does look like the same Intake manifold that I have, are you willing to sell it?

Mine definitely looks cracked, I don't know if its leaking anything given all the sealant there.

I have one I would be willing to part with, if you're still in need.

Yes!! I could still use one. Do you have pics to make sure its the same? And thank you! Also how much you be willing to sell it to me for.