I need the casting numbers for a factory 4bbl intake manifold for an Olds 455. Looking for 1970 - 1971 non-EGR with the choke stove, many thanks.

 

My reference book shows:
1970-72 4bbl Automatic Transmission 404521
1970-71 4bbl Manual Transmission 407567

John

 

1970-71 cast iron MT 407567 1970-72 AT cast iron 404521

 

What's the difference in an intake for an AT vs. an intake for MT? Are they interchangable?

 

Many thanks for the help with those numbers! Sorry I don't know the difference between the two intakes but I'm willing to bet someone here does.

 

The difference is probably just the number on it. Interchangeable-yes, but not for a number correct car.

It would be nice if there was a deeper plenum, or more runner volume on the 4 speed unit.
According to my Mondello manual, the part #413111 (1973 455 4 bbl with egr) had a slightly larger "flow area" (2.68, as opposed to 2.50...whatever), as compared to the other non Toronado intake manifolds made by Oldsmobile.
Jim

 

The difference is that the MT intakes have the fitting for the PCV valve, like the W-30 intakes. The AT intakes do not.

 

Picked up my intake today, a very clean original piece and the correct number (404521) casting for my application! Thanks again for the help with getting the correct casting numbers!

 

HI In a related subject, I have a stock 1970, 455 Oldsmobile intake manifold and I purchased some bolts from Mondello's. There are three different sized bolts in the package. Question is, do you know there is a bolt pattern for these longer bolts go or should they will be the same size?

 

No, actually the bolt lengths really aren'r related to an eight year old thread on casting numbers...

In any case, a stock iron 1970 intake should use bolts that are all the same length. Depending on your accessory brackets, you may or may not need one or two bolts with a threaded stud on the head. In some cases, the intake may be thinner at the bolt locations on either side of the heat crossover in the center of the intake. If so, use the shorter bolts there.

 

Thank you for the information, this is what I was thinking, but the intake manifolds is off at the powder coders and I can not confirm.

 

Since we're dredging up an old thread here, I noticed the letter 'L' cast along the front runners on this 404521 intake. I'm asking if that's significant because the stock heater control valve had to be adapted to fit the 1/2" threaded port. Everything works as it should, I'm just curious what intake I ended up with here.

 

L intake is for a 70.

 

I have been told that an edelbrock performer 2151 is too high to fit under the hood of my 67 olds 442 any body know for sure